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Birth defects linked to increased recombination among older mothers
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Older mothers have increased recombination rates and deregulated recombination events, putting them at higher risk for having babies with birth defects, according to a recently published study in Nature Communications.
“The placement of female recombination events appears to become increasingly deregulated with maternal age,” Adam Auton, PhD, of the department of genetics at Albert Einstein College of Medicine, Bronx, NY, and colleagues wrote.
Adam Auton
Researchers studied data on 4,209 families, collected from 23andMe Inc. database – a direct-to-consumer genetic testing company – to examine patterns of recombination.
Differences in the distribution of recombination events between the sexes was evident, with a mean of 41.6 autosomal recombination events per gamete in women (95% CI, 41.4-41.9) and 26.6 in men (95% CI, 26.5-26.7). A linear regression analysis showed an additional 0.067 (P = .002) events per year in older women, but there was no similar effect in men. In women older than 38.8 years, recombination events jumped from 0.047 events per year to 2.990 events per year. Mothers aged ≥ 39 years averaged 2.51 more events per year compared to younger mothers (P = .0005).
However, men did show a 4.6% higher rate of recombination events occurring within hotspots, compared to women (P = 1.1 x 10 –69). There were no significant association between events in hotspots and maternal age.
Recombination events deregulated with older age and occurred closer to each other in older mothers, according to the researchers.
“Our study adds to the understanding of the basic biology of meiosis and how recombination shapes the evolution of the human species. In the long run, it may help us understand how aneuploidy or certain types of genetic mutation can occur through failures of recombination,” Auton said in a press release. – by Casey Hower
Disclosure: Auton reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.