A Systematic Review of Y Chromosome Conservation Across Vertebrates: Mechanisms and Evolutionary Implications

Document Type

Article

Publication Title

Journal of the Anatomical Society of India

Abstract

Background: The Y chromosome has a much smaller effective population size—being present at only about one-quarter the frequency of autosomes—and, because selection acts on the chromosome as a whole rather than on individual genes, it is more prone to the accumulation of deleterious mutations and progressive genetic deterioration. While beneficial alleles may be lost if they arise on a degenerated Y chromosome, harmful mutations may be repaired by genetic hitchhiking. Aim: Sequence conservation, pseudoautosomal areas, gene duplication, and dosage compensation mechanisms are among the genetic and epigenetic elements that affect Y chromosome conservation in animals. Structural changes, repetitive sequences, and extensive regions of heterochromatin contribute to the instability and gradual degeneration of the Y chromosome. Y chromosome studies should be examined for methodological flaws and research gaps in order to inform future studies on the evolution of vertebrate sex chromosomes. Methodology: According to Page et al. (2021), this systematic review adheres to the Preferred Reporting Items for Systematic reviews and Meta-analyses 2020 guidelines. Randomized, observational, and laboratory studies, as well as meta-analyses, have investigated Y chromosome conservation across various animal and vertebrate species. Excluded will include review studies, case reports, observational studies, and randomized controlled trials that employ human evaluation. Seven hundred thirty-one records in total were initially acquired, 674 of which were from PubMed databases and the remaining 57 from other sources, such as websites and other databases. After fulfilling the inclusion requirements, 14 studies were ultimately selected for the systematic review. Results: Different Y chromosome evolutionary trends among animals are shown by comparative genomic investigations. Fish and amphibians display gradual degeneration, but primates display conservation of Y-linked genes. Studies on reptiles and birds emphasize the structural dynamics of the sex chromosome. Results cast doubt on linear gene degradation models, highlighting the role of evolutionary limitations, functional retention, and selective pressures in the evolution of the Y chromosome in vertebrates. Conclusion: Elucidation of sex chromosome evolution demands a comprehensive phylogenomic analysis of Y chromosome in vertebrates, including fish, birds, reptiles, amphibians, and mammals.

First Page

263

Last Page

277

DOI

10.4103/jasi.jasi_72_25

Publication Date

7-1-2025

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