The degeneration of Y chromosomes.

By B. Charlesworth, D. Charlesworth. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 2000

913 citations recorded by the source corpus.

Y chromosomes are genetically degenerate, having lost most of the active genes that were present in their ancestors. The causes of this degeneration have attracted much attention from evolutionary theorists. Four major theories are reviewed here: Muller's ratchet, background selection, the Hill Robertson effect with weak selection, and the 'hitchhiking' of deleterious alleles by favourable mutations. All of these involve a reduction in effective population size as a result of selective events occurring in a non-recombining genome, and the consequent weakening of the efficacy of selection. We review the consequences of these processes for patterns of molecular evolution and variation at loci on Y chromosomes, and discuss the results of empirical studies of these patterns for some evolving Y-chromosome and neo-Y-chromosome systems. These results suggest that the effective population sizes of evolving Y or neo-Y chromosomes are severely reduced, as expected if some or all of the hypothesized processes leading to degeneration are operative. It is, however, currently unclear which of the various processes is most important; some directions for future work to help to resolve this question are discussed.

Subfields: Genetics

View Paper: https://www.semanticscholar.org/paper/9f182560e6a4b0201d8a78986d26ab8aa0de0924

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Citations in the corpus

Genomic Consequences of Outcrossing and Selfing in Plants (2008, background): “Keywords: inbreeding, genome evolution, recombination, transposable elements, genome size, deleterious mutation.”
Evolution of dioecy and sex chromosomes via methylation driving Muller's ratchet (2003, methodology): “…to Muller’s ratchet for the evolution of sex chromosomes is that virtually all modern biologists working on this problem have used Drosophila as their study organism (Charlesworth, 1978; Rice, 1987b; Charlesworth, 1991; Steinemann & Steinemann, 1992; Rice, 1996; Charlesworth & Charlesworth, 2000).”
Steps in the evolution of heteromorphic sex chromosomes (2005, background): “…of the early stages of sex chromosome evolution show how the lack of recombina- tion between the sex chromosomes may have arisen (Charlesworth and Charlesworth, 1978), and how this can lead to genetic degeneration of the heterozygous sex chromosome (reviewed in Charlesworth and Charlesworth, 2000).”
Weird Animal Genomes and the Evolution of Vertebrate Sex and Sex Chromosomes (2008, background): “Why are mutated and deleted Y chromosomes not selected against, particularly if many genes lost have essential functions in fertility? The degradation process has been explored in detail elsewhere (3, 10, 30).”