Reporter: Aviva Lev-Ari, PhD, RN

• Brian Owens

The tendency of sperm to swim alone makes the cells ideal for single-cell genomics. Adam Auton, a statistical geneticist at Albert Einstein College of Medicine in New York is using sperm to study recombination, the process that shuffles genes during the formation of germ cells and therefore influences which genes are inherited. “Recombination is one of the fundamental forces that shapes genetic diversity,” he says. “In recent years we’ve learned that there is considerable variation in the recombination rate between different populations, between the sexes and even between individuals.” But pinning down the rate in people once seemed impossible because it would have required finding individuals with hundreds of children and sequencing their genomes.

The ability to sequence single cells meant that researchers could take another approach. Working with a team at the Chinese sequencing powerhouse BGI, Auton sequenced nearly 200 sperm cells and was able to estimate the recombination rate for the man who had donated them. The work is not yet published, but Auton says that the group found an average of 24.5 recombination events per sperm cell, which is in line with estimates from indirect experiments². Stephen Quake, a bioengineer at Stanford University in California, has performed similar experiments in 100 sperm cells and identified several places in the genome in which recombination is more likely to occur. The location of these recombination ‘hotspots’ could help population biologists to map the position of genetic variants associated with disease.

Quake also sequenced half a dozen of those 100 sperm in greater depth, and was able to determine the rate at which new mutations arise: about 30 mutations per billion bases per generation³, which is slightly higher than what others have found. “It’s basically the population biology of a sperm sample,” Quake says, and it will allow researchers to study meiosis and recombination in greater detail.

SOURCE:  

VIEW ARTICLE IN NATURE

http://www.nature.com/news/genomics-the-single-life-1.11710#/genome