Scheinfeldt, L. B. | Search bioRxiv

bioRxiv2025

New iPSC resource with long-read whole genome sequencing characterizations for enhanced in vitro modeling

Here we present a new iPSC resource of apparently healthy subject biospecimens available to the research community through the National Institute of General Medical Sciences Human Genetic Cell Repository (NIGMS Repository). This resource includes five iPSCs and matched parental cell lines with accompanying publicly available, HiFi whole-genome sequencing data. Structural variant (SV) and single nucleotide variant (SNV) concordance between iPSC and parental lines was generally high; however, we found a notable reduction in concordance between the iPSC reprogrammed with retroviral reprogramming and its parental line consistent with previous work showing newer Sendai approaches to be more robust in preserving genomic integrity. This iPSC resource additionally includes pharmacogenomic and human leukocyte antigen (HLA) gene annotations as well as a set of user-friendly, web-based search tools to visualize and explore SVs and SNVs. This new resource is designed to offer a highly characterized set of in vitro models for research into cell-type specific functional characterization of genetic, genomic and pharmacogenomic variation. More generally, these renewable biospecimens and genomic data search tools are available to the scientific community to support high-quality and reproducible biomedical research.

genomics↗

bioRxiv2018

Adaptive landscape of protein variation in human exomes

The human genome contains hundreds of thousands of missense mutations. However, only a handful of these variants are known to be adaptive, which implies that adaptation through protein sequence change is an extremely rare phenomenon in human evolution. Alternatively, existing methods may lack the power to pinpoint adaptive variation. We have developed and applied an Evolutionary Probability Approach (EPA) to discover candidate adaptive polymorphisms (CAPs) through the discordance between allelic evolutionary probabilities and their observed frequencies in human populations. EPA reveals thousands of missense CAPs, which suggest that a large number of previously optimal alleles had experienced a reversal of fortune in the human lineage. We explored non-adaptive mechanisms to explain CAPs, including the effects of demography, mutation rate variability, and negative and positive selective pressures in modern humans. Our analyses suggest that a large proportion of CAP alleles have increased in frequency due to beneficial selection. This conclusion is supported by the facts that a vast majority of adaptive missense variants discovered previously in humans are CAPs, and that hundreds of CAP alleles are protective in genotype-phenotype association data. Our integrated phylogenomic and population genetic EPA approach predicts the existence of thousands of signatures of non-neutral evolution in the human proteome. We expect this collection to be enriched in beneficial variation. EPA approach can be applied to discover candidate adaptive variation in any protein, population, or species for which allele frequency data and reliable multispecies alignments are available.

evolutionary biology↗