Base by Base

Kimchi O et al., PNAS - This computational study shows that self-complementary RNA regions (palindromes) can drive sequence-specific homotypic clustering by enabling multivalent intermolecular base pairing, and that Drosophila nanos and pgc mRNAs are enriched for accessible, strong palindromes. Key terms: RNA palindromes, homotypic clustering, germ granules, nanos mRNA, phase separation.

Study Highlights:
The authors use equilibrium and nonequilibrium in silico analyses to show palindromic regions increase the likelihood of homodimer and higher-order homomultimer formation. Palindrome binding strength correlates with multimerization propensity, and accessible strong palindromes are enriched in nanos and pgc compared to length-matched Drosophila mRNAs. Out-of-equilibrium calculations indicate initial accessible palindromic interactions can favor homotypic binding despite general heterodimer preference. The framework suggests palindromes could be under evolutionary selection and predicts experimental tests using designed synthetic sequences.

Conclusion:
Palindromic, self-complementary RNA regions provide a generic mechanism for RNA self-recognition and can explain homotypic clustering in germ granules; palindrome content may be under evolutionary selection and can guide experimental tests with synthetic RNAs.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
How do RNA molecules distinguish self from non-self?

First author:
Kimchi O

Journal:
PNAS

DOI:
10.1073/pnas.2603593123

Reference:
Kimchi O, Mitchel K, Pyod AGT, Wingreen NS, Gavis ER. How do RNA molecules distinguish self from non-self? PNAS. 2026;123(15):e2603593123. doi:10.1073/pnas.2603593123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/palindromes-rna-self-recognition

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-19.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript portions describing palindromic self-recognition, equilibrium and nonequilibrium modeling, nanos/pgc enrichment, cross-species considerations, GFP tail experiment, evolutionary implications, clinical and synthetic biology implications, and study limitations.
- transcript topics: Palindromic regions as self-recognition mechanism; Equilibrium vs nonequilibrium RNA interactions; Nanos and pgc palindromes: binding strength and accessibility; GFP tail experiment and cross-context clustering; Evolutionary selection and clinical implications; Limitations of in silico modeling and need for in vitro validation

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 8
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Palindromic regions enable self-recognition and drive homotypic clustering via multivalent RNA–RNA interactions
- Nanos and pgc RNAs are enriched for accessible, strongly binding palindromes and cluster with their own type
- Out-of-equilibrium modeling shows nanos and pgc have higher homodimer propensity than typical RNAs
- Deleting palindromes abolishes homotypic bias, illustrating necessity of palindromes
- GFP mRNA with nanos tail forms its own homotypic clusters, validating palindrome-driven self-recognition across sequences
- Palindromes are proposed to be under evolutionary selection; content affects clustering across contexts

QC result: Pass.

Scartozzi AC et al., Human Genetics and Genomics Advances - This episode reviews a GWAS of speech rhythm (prosody) perception using the TOPsy task (n≈1,501 European-ancestry), reporting 14 suggestive loci, nominal enrichment for songbird vocal-learning gene sets, and polygenic links to reading and musical rhythm. Key terms: prosody, speech rhythm, genetics, musical rhythm, reading.

Study Highlights:
The authors performed a GWAS of TOPsy speech rhythm scores in ~1,501 individuals of European genetic ancestry and identified 14 loci reaching suggestive significance but no genome-wide significant hits. Gene-based analyses flagged TTLL1 and GP2 among the top genes without Bonferroni significance. Gene-set enrichment showed nominal overlap with songbird Area X vocal-learning gene sets, consistent with evolutionary convergence hypotheses. Polygenic score analyses demonstrated shared genetic influences between prosody perception and both word reading and beat synchronization, while voice-pitch PGS results were weaker.

Conclusion:
Findings provide initial genomic evidence that prosody perception is polygenic and shares genetic architecture with reading and musical rhythm, and they motivate larger, more diverse samples and scalable phenotyping (TOPsy) to validate and extend these results.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Genome-wide investigation of prosody perception: Shared genetic influences between speech rhythm, musical rhythm, and reading traits

First author:
Scartozzi AC

Journal:
Human Genetics and Genomics Advances

DOI:
10.1016/j.xhgg.2026.100581

Reference:
Scartozzi AC, Wang Y, Coleman PL, et al. Genome-wide investigation of prosody perception: Shared genetic influences between speech rhythm, musical rhythm, and reading traits. Human Genetics and Genomics Advances. 2026;7:100581. https://doi.org/10.1016/j.xhgg.2026.100581

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/genes-of-prosody-rhythm-music-reading

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-17.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing: the definition/importance of prosody and speech rhythm; TOPsy test methodology; GWAS results (no genome-wide hits, 14 suggestive loci); top gene signals (TTLL1 and GP2); cross-species birdsong gene-set enrichment (Area X); polygenic score analyses (word reading, beat synchron
- transcript topics: Definition and importance of prosody and speech rhythm; TOPsy remote 28-item test design and phenotyping; Genome-wide association results for TOPsy (n=1501 European ancestry); Gene-based GWAS signals TTLL1 and GP2; Birdsong gene-set enrichment: Area X and cross-species convergence; Polygenic score analyses: word reading and beat synchronization predicting TOPsy

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- TOPsy is a 28-item remote, auto-scored test for syllable stress (prosody) perception
- GWAS sample size: 1,501 individuals of European ancestry; λ ~ 1.0065
- No genome-wide significant variant; 14 loci reached suggestive significance (p < 5e-6)
- Top gene-based signals include TTLL1 and GP2
- Birdsong gene sets showed enrichment for Area X (Area X overlap) in humans
- Word reading PGS and beat synchronization PGS predicted TOPsy scores; voice pitch variability PGS weaker and not consistently replicated

QC result: Pass.

Kühnisch J et al., Human Genetics and Genomics Advances 7, 100598 (2026) - Case report and tissue analysis linking a homozygous TNNI3 nonsense variant (c.406C>T; p.Arg136*) to early-onset, treatment-refractory restrictive cardiomyopathy in a young child who required heart transplantation. Key terms: TNNI3, restrictive cardiomyopathy, pediatric cardiomyopathy, troponin I, protein truncation.

Study Highlights:
A 2-year-old female with severe pediatric restrictive cardiomyopathy carried a homozygous TNNI3 c.406C>T (p.Arg136*) nonsense variant. Myocardial immunostaining showed approximately 50% reduced TNNI3 protein abundance though truncated protein remained detectable. Electron microscopy revealed myofibrillar disarray, irregular Z bands, indistinct M lines, and mitochondrial hyperplasia. The clinical course was treatment refractory and led to heart transplant at 28 months, implicating variant zygosity and truncation position in phenotype determination.

Conclusion:
Biallelic truncation of TNNI3 (p.Arg136*) can cause severe early-onset pediatric restrictive cardiomyopathy, with reduced but partially stable truncated protein and severe sarcomeric pathology prompting early transplantation.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
A homozygous variant in cardiac troponin I3, TNNI3, causes severe pediatric restrictive cardiomyopathy

First author:
Kühnisch J

Journal:
Human Genetics and Genomics Advances 7, 100598 (2026)

DOI:
10.1016/j.xhgg.2026.100598

Reference:
Kühnisch J, Barnett CL, Brendel J, et al. A homozygous variant in cardiac troponin I3, TNNI3, causes severe pediatric restrictive cardiomyopathy. Human Genetics and Genomics Advances. 7:100598. https://doi.org/10.1016/j.xhgg.2026.100598

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/tnni3-arg136-pediatric-rcm

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-17.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript's representation of the genetic case, protein expression, tissue analyses, mechanistic interpretation, and genotype–phenotype implications as described in the article.
- transcript topics: RCM vs DCM distinctions; TNNI3 function in the troponin complex; Case presentation and homozygous TNNI3 variant; DNA sequencing and parental segregation; Protein expression by immunostaining; Ultrastructural TEM findings

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Homozygous TNNI3 nonsense variant c.406C>T (p.Arg136*) identified in the proband.
- Proband presented with severe restrictive cardiomyopathy (RCM) requiring heart transplantation at 28 months.
- TNNI3 protein abundance was reduced by approximately 50%, with detectable truncated protein remaining.
- TEM showed sarcomeric disarray and mitochondrial hyperplasia in explanted heart tissue.
- NMD failed to completely eliminate the truncated transcript due to exon 7 being near the end of the gene.
- Heterozygous parents were clinically healthy carriers, supporting non-penetrance of haploinsufficiency in this context.

QC result: Pass.

López-Astacio RA et al., PNAS - Analysis of 60 years of feline panleukopenia virus genomes traces the origins of canine parvovirus, identifies vaccine-derived sequences, and documents distinct evolutionary rates and capsid adaptations that enabled a host jump to dogs. Key terms: parvovirus, FPV, CPV, host jump, evolution.

Study Highlights:
Using full-genome sequencing and phylogenetics, the authors compare 60 years of FPV evolution with 47 years of CPV evolution and identify vaccine-derived sequences that cluster with early isolates. FPV evolves at roughly one-third the rate of CPV in dogs, while the CPV ancestor is closely related to European FPV-like strains and carries multiple capsid mutations linked to binding the canine transferrin receptor. Live-attenuated FPV vaccines derive from early 1960s isolates and FPV shows little antigenic selection compared to the faster-evolving CPV lineage. These patterns emphasize distinct evolutionary dynamics in reservoir versus new hosts during epidemic emergence.

Conclusion:
A single FPV-related lineage from Europe accumulated multiple capsid changes enabling canine TfR binding and gave rise to the CPV pandemic; thereafter CPV evolved approximately 3–4 times faster in dogs, while FPV in its reservoir hosts showed slow evolution with limited antigenic change and persistent vaccine-derived genomes in databases.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Distinct evolutionary patterns of endemic and emerging parvoviruses and the origin of a new pandemic virus

First author:
López-Astacio RA

Journal:
PNAS

DOI:
10.1073/pnas.2515274123

Reference:
López-Astacio RA, Wasik BR, Lee H, Voorhees IEH, Weichert WS, Adu OF, Goodman LB, Hafenstein SL, Truyen U, Parrish CR. Distinct evolutionary patterns of endemic and emerging parvoviruses and the origin of a new pandemic virus. PNAS. 2026;123(16):e2515274123. doi:10.1073/pnas.2515274123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/feline-to-canine-parvovirus-origins

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-15.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing FPV reservoir, CPV emergence, TfR binding and glycosylation barriers, VP2/other capsid mutations, evolutionary rates, vaccine-derived FPV sequences, antigenic variation, intermediate hosts, and missing ancestral link.
- transcript topics: FPV feline reservoir and CPV emergence; Transferrin receptor binding and canine TfR glycosylation barrier; VP2 mutations and host-range adaptation; Evolutionary rates FPV vs CPV and molecular clock methods; Vaccine-derived FPV sequences and vaccine filtering; Antigenic variation in FPV vs CPV and vaccine efficacy

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- CPV originated from European FPV lineage with host-range mutations enabling canine TfR binding
- CPV substitution rate in dogs is approximately 2.18×10^-4 substitutions/site/year; FPV in cats approximately 5.78×10^-5 substitutions/site/year
- Twelve nonsynonymous and ten synonymous substitutions on the CPV-2 branch; nine nonsynonymous substitutions occurred in VP2, with changes near the threefold spike affecting host ra
- FPV vaccine strains derive from 1960s isolates; many FPV-like sequences in databases are vaccine-derived or recombinant; vaccine-derived sequences can confound analyses
- FPV shows limited antigenic variation; CPV exhibits more antigenic variation, but vaccines remain broadly protective due to polyclonal responses
- Raccoons (and other noncanine hosts) proposed as intermediate hosts that could accumulate mutational combinations before canine adaptation

QC result: Pass.

Tovar A et al., Human Genetics and Genomics Advances - This episode examines a study that used a modular MPRA to test ~11,656 genomic fragments from T2D- and metabolic trait-associated regions in pancreatic beta cells, comparing upstream vs downstream positions and SCP1 vs INS promoters. The work identifies promoter- and position-dependent regulatory activity and implicates HNF1 motifs in INS promoter-specific effects. Key terms: massively parallel reporter assay, type 2 diabetes, noncoding regulation, HNF1, promoter-enhancer compatibility.

Study Highlights:
The authors screened nearly 12,000 fragments across T2D- and metabolic trait-associated regions in a pancreatic beta cell model using four MPRA configurations (up/down × SCP1/INS). They found ~6% of fragments show significant promoter bias and ~6% show position bias, with INS-preferring fragments enriched for HNF1 motifs. Targeted motif perturbation MPRA showed HNF1 motif disruption reduced activity specifically in the INS promoter context and in beta cells but not in skeletal muscle, indicating cell-type and promoter-specific regulatory dependencies. The results highlight that MPRA construct design choices materially affect detection and interpretation of regulatory activity.

Conclusion:
Promoter identity and fragment position influence MPRA-detected regulatory activity, and tissue-specific promoters (like INS) can reveal TF-dependent regulatory mechanisms (e.g., HNF1) at T2D-linked noncoding regions.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Using a modular massively parallel reporter assay to discover context-dependent regulatory activity in type 2 diabetes-linked noncoding regions

First author:
Tovar A

Journal:
Human Genetics and Genomics Advances

DOI:
10.1016/j.xhgg.2026.100606

Reference:
Tovar A, Kyono Y, Nishino K, Bose M, Varshney A, Parker SCJ, Kitzman JO. Using a modular massively parallel reporter assay to discover context-dependent regulatory activity in type 2 diabetes-linked noncoding regions. Human Genetics and Genomics Advances (2026). doi: https://doi.org/10.1016/j.xhgg.2026.100606

License:
http://creativecommons.org/licenses/by-nc-nd/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/modular-mpra-t2d-context-dependent-regulation

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-14.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the scientific content describing MPRA design parameters, library size, cell models, promoter/position bias findings, HNF1 motif associations and perturbations, and cross-tissue results as presented in the transcript.
- transcript topics: MPRA design configurations (promoter: INS vs SCP1; position: upstream vs downstream); Library scale and construction (11,656 fragments; ~13,226 sites; 198-bp fragments with adapters); Cell models used (832/13 rat beta-cell line; LHCN-M2 human skeletal muscle cells); Promoter bias findings (INS promoter bias ~73.4%; 698 fragments promoter-biased); Position bias findings (703 fragments showing upstream/downstream bias); Motif enrichment and HNF1A/B associations with INS promoter activity

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license
- episode_title

Factual Items Audited:
- MPRA design configurations: upstream vs downstream relative to INS and SCP1 promoters
- Library size: ~11,656 fragments across 4 configurations (out of ~13,226 targeted sites)
- Cell models: 832/13 rat insulinoma beta cells and LHCN-M2 human skeletal muscle myoblasts
- Promoter bias: 698/11,656 fragments show significant promoter effects; INS bias ~73.4% of promoter-biased fragments
- Position bias: 703/11,656 fragments show significant upstream/downstream bias
- HNF1 motif enrichment among INS-promoter-biased fragments; NKX6.1 also involved

QC result: Pass.

Widding-Havneraas T et al., PNAS - This study uses genetic variation related to educational attainment as a quasi-experimental instrument (Mendelian randomization) together with Norwegian registry data to estimate the causal return to an additional year of schooling on labor-market earnings. Key terms: returns to education, Mendelian randomization, polygenic index, Norwegian registries, life-cycle earnings.

Study Highlights:
The authors triangulate OLS, sibling and twin fixed-effects, and Mendelian randomization (MR) using a 335-SNP polygenic index to estimate returns to schooling in Norwegian population and MoBa samples. OLS estimates an additional year of schooling raises prime-age earnings by about 5.9%, sibling FE by 5.3%, MZ twin FE by 3.3%, and MR by 8.0% (with a Norway-only MR estimate of 9.7%). Life-cycle analyses show negative early-career returns that turn positive around age 27 and grow thereafter. Internal rates of return across models exceed the market interest rate, indicating education is profitable over the life cycle.

Conclusion:
Using genetically informed quasi-experiments, one additional year of schooling causally increases annual earnings (MR ~8%), and education appears to pay off across the life cycle.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Estimating returns to education using the genetic lottery

First author:
Widding-Havneraas T

Journal:
PNAS

DOI:
10.1073/pnas.2537049123

Reference:
Widding-Havneraas T, Demange PA, Zachrisson HD, Borgen N, Ystrom E, Elwert F. Estimating returns to education using the genetic lottery. PNAS. 2026;123(15):e2537049123. https://doi.org/10.1073/pnas.2537049123. Published April 8, 2026.

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/genetic-lottery-returns-to-education

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-13.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Substantive audit focused on the episode’s discussion of methodology, key numerical results, lifecycle interpretation, and robustness checks as presented in the original article.
- transcript topics: Causality vs correlation in education and earnings; Mendelian randomization as a quasi-experiment; 335-SNP polygenic index as educational attainment instrument; Comparison across identification strategies: OLS, sibling, DZ/MZ twins, MR; Compliers and nonshared environments; Life-cycle returns and age-27 crossover

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license
- episode_title
- episode_number
- season

Factual Items Audited:
- MR estimate: 8.0% increase in lifetime earnings per additional year of schooling
- OLS estimate: 5.9% increase per additional year of schooling
- Norway-only MR estimate: 9.7% per additional year
- Internal rate of return (IRR) to schooling: 10.1%
- Crossover age where returns become positive: about age 27
- Women experience higher financial returns to schooling than men

QC result: Pass.

Imai A et al., Proceedings of the National Academy of Sciences (PNAS) - This paper shows that alternative splicing of a 12-nt microexon (meB) in Ptprd is regulated by a genetic intronic enhancer and an activity-dependent intronic silencer to set region- and age-specific ratios of PTPRD splice variants. Manipulating these intronic elements in mice changes the proportion of meB-containing isoforms without altering total PTPRD protein and produces distinct behavioral consequences. Key terms: microexon, alternative splicing, PTPRD, synaptogenesis, behavior.

Study Highlights:
The authors mapped eight Ptprd splice variants across brain regions and ages and found neuronal activity induces rapid meB skipping. They identified a 316-bp intronic splicing enhancer (ISE) whose heterozygous deletion reduced meB selection by ~25% and caused broad sensory, motor, social, and emotional deficits. They also identified a 420-bp intronic splicing silencer (ISS) required for activity-dependent meB skipping; deletion of the ISS produced selective impairments in motor learning and remote cued fear memory. These results indicate that the spatiotemporal and activity-dependent AS code of a four–amino-acid microexon sculpts synaptogenic properties and behavioral development.

Conclusion:
Spatiotemporal and activity-dependent alternative splicing of a single four–amino-acid microexon in Ptprd controls the balance of PTPRD splice variants and is essential for normal behavioral development in mice.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Alternative microexon splicing code for a four - amino acid peptide of PTPRD governs behavioral development

First author:
Imai A

Journal:
Proceedings of the National Academy of Sciences (PNAS)

DOI:
10.1073/pnas.2515310123

Reference:
Imai A, Izumi H, Ito N, et al. Alternative microexon splicing code for a four-amino acid peptide of PTPRD governs behavioral development. Proc Natl Acad Sci U S A. 2026;123(15):e2515310123. doi:10.1073/pnas.2515310123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/ptprd-microexon-ep340

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-12.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the scientific narrative in the transcript related to Ptprd microexon meB regulation, the regulatory elements ISE and ISS, bead-coculture experiments, in vivo CRISPR mouse models (ISE and ISS mutations), activity-dependent skipping, and the resulting behavioral and learning/memory phenotypes, as well as the pro
- transcript topics: Ptprd microexon meA3, meA6, meB and eight splice variants; Bead coculture assay to test synaptogenicity and ligand interactions (Shank2, gephyrin, NLGN3); Genetic regulation of meB: intronic splicing enhancer (ISE); Activity-dependent regulation of meB: intronic splicing silencer (ISS); In vivo CRISPR mouse models: Ptprd+/dISE, PtprddISE/dISE, PtprddISS/dISS; Neuronal activity and rapid meB skipping (1 hour after KCl)

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Eight Ptprd splice variants arise from combinations of meA3, meA6, and meB, with region- and age-specific distributions
- An upstream intronic splicing enhancer (ISE) of Ptprd meB regulates inclusion; its deletion reduces meB selection by about 25% with no change to total PTPRD
- An activity-dependent intronic splicing silencer (ISS) regulates meB skipping; deletion increases meB exclusion to near 100% and impairs motor learning and remote fear memory
- Neuronal activity (KCl) rapidly increases meB skipping within 1 hour
- A 50% reduction in total PTPRD with normal splice ratios yields fewer behavioral abnormalities than a 25% shift in splice ratio
- Dysregulation of Ptprd microexons is linked to ASD-like phenotypes and may be therapeutically targetable via splicing ratio modulation

QC result: Pass.

Korfmann K et al., Proceedings of the National Academy of Sciences (PNAS) - This episode examines cxt, a decoder-only transformer that performs next-coalescence prediction by translating local mutational context into pairwise TMRCA estimates. Trained on stdpopsim simulations, cxt delivers rapid, scalable coalescence-time inference, calibrated posteriors, and practical adaptations for empirical data. Key terms: language models, coalescent theory, uncertainty, stdpopsim, simulation-based inference.

Study Highlights:
The authors develop cxt, an autoregressive transformer that predicts discretized pairwise coalescence times from SFS-weighted mutation windows, framing TMRCA inference as a translation task. Trained on extensive stdpopsim simulations, cxt matches state-of-the-art accuracy in well-specified settings and generalizes to many out-of-sample species with some loss of accuracy. The model produces well-calibrated approximate posteriors, enables rapid GPU inference (millions of predictions in minutes), and can be fine-tuned or adapted for large Ne, missing data, or small sample sizes. Applications to human and Anopheles genomes recover known signals at LCT, HLA, inversion regions, and the Rdl insecticide-resistance locus.

Conclusion:
cxt reframes coalescent inference as a language-modeling problem, providing a fast, scalable, and adaptable tool that learns priors from simulations to infer local TMRCA and aggregate demography while offering uncertainty quantification through approximate posteriors.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Accessible, realistic genome simulation with selection using stdpopsim

First author:
Korfmann K

Journal:
Proceedings of the National Academy of Sciences (PNAS)

DOI:
10.1073/pnas.2518956123

Reference:
Korfmann K., Pope N. S., Meleghy M., Tellier A., Kern A. D. Coalescence and translation: A language model for population genetics. Proc. Natl. Acad. Sci. U.S.A. 2026;123:e2518956123. doi:10.1073/pnas.2518956123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/cxt-language-model-for-population-genetics

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-11.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited transcript sections describing the cxt model (architecture and next-coalescence prediction), training on stdpopsim, performance benchmarks, generalization to unseen species, empirical data applications (LCT, HLA, Rdl), missing data handling/adapters, and environmental considerations.
- transcript topics: ARG basics and coalescent theory as context; cxt architecture: decoder-only transformer and next-coalescence prediction; input encoding: mutational densities, SFS, rotary embeddings; training data: stdpopsim simulations and catalog breadth; benchmark comparisons: Singer+Polegon and SMC++; generalization to stdpopsim v0.3 and unseen species

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 8
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- cxt is a decoder-only transformer that autoregressively predicts local coalescence times (TMRCA) via next-coalescence prediction
- Trained on stdpopsim simulations; generalizes across demographies, including unseen species
- Inference is fast (millions of TMRCAs in minutes) on a single NVIDIA A100 GPU
- cxt yields well-calibrated approximate posteriors for TMRCA
- Compared to Singer+Polegon and SMC++, cxt is competitive and often superior in well-specified/out-of-distribution scenarios
- Empirical data show clear LCT and HLA signals in humans and Rdl dynamics in Anopheles; missing data handling improves robustness

QC result: Pass.

Tibbe D et al., The American Journal of Human Genetics - This study identifies bi-allelic hypomorphic WDHD1 variants in 17 subjects with a clinical spectrum from fetal lethality to microcephalic primordial dwarfism and characterizes cellular defects in patient-derived cells linked to replisome dysfunction. Key terms: WDHD1, microcephalic primordial dwarfism, replication stress, sister chromatid cohesion, splicing variants.

Study Highlights:
Researchers found bi-allelic WDHD1 variants in 17 subjects presenting with intrauterine growth retardation, microcephaly and a spectrum of organ abnormalities including neonatal acute liver failure. Several intronic variants cause aberrant splicing and markedly reduced WDHD1 protein levels in fibroblasts. Subject-derived cells showed slowed replication fork progression, impaired G1-to-S transition, increased spontaneous DNA damage, abnormal nuclear morphology, and elevated premature sister chromatid separation, supporting a role for WDHD1 in replisome stability and cohesion.

Conclusion:
Hypomorphic bi-allelic WDHD1 variants cause an autosomal recessive microcephalic primordial dwarfism spectrum by reducing WDHD1 protein and impairing replication fork stability, genome integrity, and sister chromatid cohesion, establishing WDHD1 as essential for normal human growth and development.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Bi-allelic WDHD1 variants cause microcephalic primordial dwarfism

First author:
Tibbe D

Journal:
The American Journal of Human Genetics

DOI:
10.1016/j.ajhg.2026.03.010

Reference:
Tibbe D., Vogt M.R., Holling T., et al. Bi-allelic WDHD1 variants cause microcephalic primordial dwarfism. The American Journal of Human Genetics. 2026. https://doi.org/10.1016/j.ajhg.2026.03.010

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/wdhd1-microcephalic-primordial-dwarfism

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-10.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript's coverage of WDHD1 function as replisome scaffold; intronic WDHD1 variants and splicing; DNA fiber assay and replication fork dynamics; γH2AX signaling; nuclear morphology; PCS; and liver pathology in MPD.
- transcript topics: WDHD1 as replisome scaffold; intronic WDHD1 variants and splicing; DNA fiber assay and replication fork speed; γH2AX DNA damage signaling; nuclear morphology and lamin B1; premature sister chromatid separation (PCS)

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- 17 subjects from 14 families with bi-allelic WDHD1 variants and MPD spectrum
- intronic WDHD1 variants cause aberrant splicing and markedly reduced WDHD1 protein levels in patient-derived cells
- WDHD1 acts as replisome scaffolding to stabilize replication forks and maintain genome integrity
- replication fork progression is slowed and there is increased spontaneous DNA damage (γH2AX); nuclear morphology is disrupted; PCS increased
- acute liver failure observed in a subset of neonatal subjects; liver vulnerability discussed in the context of replication stress and polyploidization

QC result: Pass.

Katzourou IK et al., The American Journal of Human Genetics - Population analysis of ~459,000 UK Biobank participants shows that carriers of neurodevelopmental CNVs (ND-CNVs) have higher odds of co-occurring internalizing (depression, anxiety, somatic) and cardiometabolic conditions (hypertension, dyslipidemia, obesity, T2D, CKD). Effects are stronger for deletions than duplications, greater in females, and linked to the number of haploinsufficient genes within deletions. Key terms: copy-number variants, multimorbidity, internalizing disorders, cardiometabolic, UK Biobank.

Study Highlights:
Using CNV calls and linked EHRs in the UK Biobank, the authors tested associations between 54 ND-CNVs and combinations of internalizing and cardiometabolic conditions (ICM-MM). Aggregated ND-CNV carriers (n≈7,546; ~1.6%) had higher odds of ICM-MM (OR range 1.21–1.57) and a higher ICM-MM frequency (14.2% vs 11.5%). Deletions showed stronger effects than duplications and the number of haploinsufficient genes in deletions was associated with greater ICM-MM risk. No robust interactions were detected between ND-CNV status and polygenic risk scores after multiple testing correction.

Conclusion:
ND-CNVs increase risk of internalizing–cardiometabolic multimorbidity at the population level, especially for deletions and in females, suggesting the need for heightened clinical monitoring of carriers.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Neurodevelopmental copy-number variants increase risk of internalizing and cardiometabolic multimorbidity: Findings from the UK Biobank

First author:
Katzourou IK

Journal:
The American Journal of Human Genetics

DOI:
10.1016/j.ajhg.2026.02.021

Reference:
Katzourou IK, LINC consortium, Barroso I, et al. Neurodevelopmental copy-number variants increase risk of internalizing and cardiometabolic multimorbidity: Findings from the UK Biobank. The American Journal of Human Genetics. 2026;113:1–11. https://doi.org/10.1016/j.ajhg.2026.02.021

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00

Official website https://basebybase.com

On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/nd-cnv-internalizing-cardiometabolic-multimorbidity

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-08.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited transcript sections covering ND-CNV–ICM-MM association, UK Biobank design and CNV calling, dosage-sensitivity (haploinsufficient vs triplosensitive), deletion vs duplication effects (notably 16p11.2), sex differences, PRS interaction analyses, and clinical implications including multidisciplinary care and casca
- transcript topics: Definition of ND-CNVs and ICM-MM; UK Biobank cohort size, CNV calling methods (PennCNV); Dosage sensitivity: haploinsufficient vs triplosensitive genes; Deletion vs duplication effects on ICM-MM and obesity; 16p11.2 region emphasis; Sex differences in ND-CNV associations

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- ND-CNVs increase risk of internalizing–cardiometabolic multimorbidity (ICM-MM) in UK Biobank with OR 1.21–1.57 and 14.2% vs 11.5% prevalence
- Deletions show stronger effects than duplications; 16p11.2 region deletions are notable
- The number of haploinsufficient genes within deletions is associated with higher ICM-MM; duplications' triplosensitive genes do not show the same pattern
- No robust ND-CNV × PRS interactions after multiple-testing correction; nominal interactions present in some PRS analyses
- Sex differences: higher risk in females for certain ND-CNV associations (e.g., T2D, internalizing)
- Survival bias in UK Biobank implies observed effect sizes are conservative lower bounds

QC result: Pass.