The human Y chromosome is not likely to disappear

January 09, 2014

Is the male Y chromosome at risk of being lost? Recent work by Dr Wilson Sayres and colleagues at UC Berkeley, published in PLOS Genetics, demonstrates that the genes on the Y chromosome are important: they have probably been maintained by selection. This implies that despite its dwindling size, the Y chromosome will be sticking around.

The human Y chromosome contains 27 unique genes, compared to thousands on other chromosomes. Some mammals have already lost their Y chromosome (despite still having males, females and normal reproduction); this has led some researchers to speculate that the Y chromosome is superfluous.

As the X and Y chromosomes evolved, male-specific genes became fixed on the Y chromosome. Some of these genes were detrimental to females, so the X and Y chromosomes stopped swapping genes. This meant the Y chromosome was no longer able to correct mistakes efficiently and has thus degraded over time.

There is low genetic diversity in the human Y chromosome, and Dr Wilson Sayres and colleagues were able to precisely measure this by comparing variation on a person's Y chromosome with variation on that person's other 22 chromosomes, the X chromosome and the mitochondrial DNA. The researchers then showed that this low genetic diversity cannot be explained solely by a reduction in the number of males passing on their Y chromosome (successfully fathering male offspring). Instead, the low diversity must also result from natural selection, in this case purifying selection (the selective removal of deleterious alleles).

The movements of human populations around the world are tracked by variations in the Y chromosome. The increased understanding provided by this research will improve estimates of humans' evolutionary history.
-end-


PLOS

Related Chromosomes Articles from Brightsurf:

Cancer's dangerous renovations to our chromosomes revealed
Cancer remodels the architecture of our chromosomes so the disease can take hold and spread, new research reveals.

Y chromosomes of Neandertals and Denisovans now sequenced
An international research team led by Martin Petr and Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has determined Y chromosome sequences of three Neandertals and two Denisovans.

Female chromosomes offer resilience to Alzheimer's
Women live longer than men with Alzheimer's because their sex chromosomes give them genetic protection from the ravages of the disease.

New protein complex gets chromosomes sorted
Researchers from the University of Tsukuba have identified a novel protein complex that regulates Aurora B localization to ensure that chromosomes are correctly separated during cell division.

Breaking up is hard to do (especially for sex chromosomes)
A team of scientists at the Sloan Kettering Institute has discovered how the X and Y chromosomes find one another, break, and recombine during meiosis even though they have little in common.

Exchange of arms between chromosomes using molecular scissors
The CRISPR/Cas molecular scissors work like a fine surgical instrument and can be used to modify genetic information in plants.

How small chromosomes compete with big ones for a cell's attention
Scientists at the Sloan Kettering Institute have solved the puzzle of how small chromosomes ensure that they aren't skipped over during meiosis, the process that makes sperm and egg.

GPS for chromosomes: Reorganization of the genome during development
The spatial arrangement of genetic material within the cell nucleus plays an important role in the development of an organism.

Extra chromosomes in cancers can be good or bad
Extra copies of chromosomes are typical in cancerous tumor cells, but researchers taking a closer look find that some extra copies promote cancer growth while others actually inhibit cancer metastasis.

X marks the spot: recombination in structurally distinct chromosomes
A recent study from the laboratory of Stowers Investigator Scott Hawley, PhD, has revealed more details about how the synaptonemal complex performs its job, including some surprising subtleties in function.

Read More: Chromosomes News and Chromosomes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.