Granddaughters are favourites of their grandmothers as genetically they share more common traits than grandsons, says a new study.
Researchers at Cambridge University have found that a grandmother’s love for her grandchildren is partially rooted in DNA — she shares most genes with her son’s daughters and the least with her son’s sons.
“Our sex-specific analysis shows that paternal grandmothers have a consistent opposite effect on boys and girls,” the researchers said, adding that a child may give off “signals” that make it easy for grandmothers to work out how close they are genetically.
The clues may be in smell form, or may be as simple as facial resemblance, The Daily Telegraph reported.
The researchers first used the laws of inheritance to work out how genetically similar a woman is to her children’s children and found that a grandmother and a grandchild share around a quarter of their genes.
But differences in the way the genes on the X chromosome are passed through the generations mean that some grandchildren share more than this.