Format

Send to

Choose Destination
Sci Rep. 2020 Feb 7;10(1):2170. doi: 10.1038/s41598-020-58997-2.

Extinction of chromosomes due to specialization is a universal occurrence.

Author information

1
University of Missouri-Kansas City School of Medicine, Department of Biomedical and Health Informatics, Kansas City, 64108, Missouri, USA. jw84d@mail.umkc.edu.
2
Kansas State University College of Veterinary Medicine, Department of Diagnostic Medicine/Pathobiology, Olathe, 66061, Kansas, USA.
3
University of Missouri-Kansas City School of Medicine, Department of Biomedical and Health Informatics, Kansas City, 64108, Missouri, USA.
4
University of Missouri-Kansas City School of Biological and Chemical Sciences, Department of Molecular Biology and Biochemistry, Kansas City, 64108, Missouri, USA.

Abstract

The human X and Y chromosomes evolved from a pair of autosomes approximately 180 million years ago. Despite their shared evolutionary origin, extensive genetic decay has resulted in the human Y chromosome losing 97% of its ancestral genes while gene content and order remain highly conserved on the X chromosome. Five 'stratification' events, most likely inversions, reduced the Y chromosome's ability to recombine with the X chromosome across the majority of its length and subjected its genes to the erosive forces associated with reduced recombination. The remaining functional genes are ubiquitously expressed, functionally coherent, dosage-sensitive genes, or have evolved male-specific functionality. It is unknown, however, whether functional specialization is a degenerative phenomenon unique to sex chromosomes, or if it conveys a potential selective advantage aside from sexual antagonism. We examined the evolution of mammalian orthologs to determine if the selective forces that led to the degeneration of the Y chromosome are unique in the genome. The results of our study suggest these forces are not exclusive to the Y chromosome, and chromosomal degeneration may have occurred throughout our evolutionary history. The reduction of recombination could additionally result in rapid fixation through isolation of specialized functions resulting in a cost-benefit relationship during times of intense selective pressure.

Supplemental Content

Full text links

Icon for Nature Publishing Group Icon for PubMed Central
Loading ...
Support Center