A new large-scale analysis reveals that certain individuals carry a gene variant that increases their likelihood of having daughters over sons.
In the recent study, researchers analyzed the genetic data of approximately 450,000 males and females from the UK Biobank.
They found that the gene variant rs144724107 increases an individual’s chances of having a daughter by 10%. This means that for a specific pregnancy, an individual with this gene has a 60% chance of having a daughter, as opposed to the expected 50/50 ratio.
The research team is still unclear whether it is the mother, the father, or both who need to carry this gene for it to influence the likelihood of having a daughter.
Gene variant rs144724107 may increase the likelihood of having daughters – (Image: iStockphoto).
Additionally, the team is yet to determine the exact mechanism by which the gene variant rs144724107 increases the chances of having daughters. However, they know that in DNA molecules, rs144724107 is located near a member of the ADAMTS gene family—a group of genes associated with sperm production and fertilization. This suggests that rs144724107 could influence gender by affecting the expression of this gene.
According to LiveScience on October 24, this finding may support Fisher’s principle, which argues that, for most of the time, sexually reproducing organisms will produce equal numbers of males and females.
Professor Jianzhi Zhang from the University of Michigan (USA) explained that this means if a population has more males than females, evolutionary pressure will favor gene variants that increase the number of females to balance the sex ratio. The reverse would also occur if there were more females than males.
To validate Fisher’s principle, researchers need to identify gene variants that influence an individual’s likelihood of having male or female offspring. Such variants in humans are challenging to detect, partly because humans tend to have fewer children.
However, thanks to the large-scale data from the UK Biobank, the research team identified the variant rs144724107, which was found in only 0.5% of the 450,000 individuals analyzed. They also believe that other variants may exist that also affect the likelihood of having sons or daughters.
The findings of this research will need to be confirmed in other populations across different countries. Additionally, the team will need to investigate whether similar variants exist in the genomes of more diverse populations, as this study only included individuals of European ancestry.
The research has been published in the journal Proceedings of the Royal Society B: Biological Sciences.
