{"entity": "publication", "iuid": "07717dd454dd4b6fa8e6174d5c495619", "timestamp": "2026-10-26T00:00:40.518Z", "links": {"self": {"href": "https://publications.scilifelab.se/publication/07717dd454dd4b6fa8e6174d5c495619.json"}, "display": {"href": "https://publications.scilifelab.se/publication/07717dd454dd4b6fa8e6174d5c495619"}}, "title": "Selective Regimes and Evolutionary Dynamics of Z and W Gametologs Across an Expanded Avian Neo-Sex Chromosome.", "authors": [{"family": "Ellerstrand", "given": "Simon J", "initials": "SJ", "orcid": "0000-0003-2674-6997", "researcher": {"href": "https://publications.scilifelab.se/researcher/5ed13c7732674cc992f2356848b97a7b.json"}}, {"family": "Hansson", "given": "Bengt", "initials": "B", "orcid": "0000-0001-6694-8169", "researcher": {"href": "https://publications.scilifelab.se/researcher/01f0144e207c41dcbc4d5aec68690e4b.json"}}], "type": "journal article", "published": "2026-08-01", "journal": {"title": "Genome Biol Evol", "issn": "1759-6653", "volume": "18", "issue": "8", "issn-l": "1759-6653"}, "abstract": "Sex chromosome evolution is characterized by Y/W degeneration and its consequences for selection on X/Z-linked recessive mutations in the heterogametic sex, yet how functional constraints modulate the evolutionary dynamics of Z-W gametologs remains poorly resolved. We addressed this question in larks (Alaudidae), a lineage carrying enlarged neo-sex chromosomes with multiple evolutionary strata formed through repeated translocations and successive recombination-suppression events. Using whole-genome sequences of males and females of two Alauda species, we analysed 1,759 Z-W gametologs. We found that W-gene degeneration was governed primarily by evolutionary time and intrinsic gene features: long genes were lost earliest, although this tendency was mitigated by gene essentiality, as indicated by high haploinsufficiency scores. Z-linked genes lacking a functional W counterpart exhibited higher nonsynonymous divergence than Z genes retaining a functional W, consistent with selection-driven faster-Z evolution. The strongest signature of purifying selection, comparable to that of pseudoautosomal genes, was observed in haploinsufficient Z-linked genes, which were also more likely to retain W gametologs. Although W genes generally diverged faster, their selection signatures covaried with those of Z and with haploinsufficiency, suggesting partially shared Z-W evolutionary dynamics. Notably, a small subset of W genes showed intensified or positive selection, including several genes associated with putative female-specific functions. Together, our results demonstrate that gene essentiality slows functional divergence on both Z and W, modulates faster-Z dynamics and enables key W genes to remain functional-and potentially advantageous for females-for millions of generations after recombination cessation.", "doi": "10.1093/gbe/evag204", "pmid": "42574665", "labels": {"National Genomics Infrastructure": "Service", "NGI Short read": "Service", "NGI Uppsala (SNP&SEQ Technology Platform)": "Service"}, "xrefs": [{"db": "pmc", "key": "PMC13524101"}, {"db": "pii", "key": "8758529"}], "notes": [], "created": "2026-10-23T12:21:53.353Z", "modified": "2026-10-23T12:21:53.377Z"}