via Christoffer Lybekk

Older generations are more likely to marry someone with similar ancestry to themselves than younger generations are. This trend has the potential to change the genetics of a community in such a way as to create bias in genetic population studies. The report, which used the genetic information of participants in the Framingham Heart Study (FHS) in Massachusetts, was published in PLOS Genetics this week.

In the past, most people have chosen a spouse from within their local community as a result of limited travel availability. This has meant that there was an increased risk of people marrying someone who shared the same ancestry, leading to a genetic structure being developed within a community that can artificially skew results in population-based studies.

The researchers observed this trend across three generations of white people involved in the FHS, which began in 1948. Using data from 879 participant pairs, they were able to conclude that people with Northern and Southern European and Ashkenazi ancestry were more likely to have chosen a spouse of the same ethnic denomination. The results also showed that successive generations demonstrated a lower chance of having a spouse with similar genetics.

The findings of this study are of particular importance for population studies. The gradual increase in genetic similarities within a community can lead to false positives when searching for disease-associated genes or loci, and skew the prevalence of different variants.

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