We’ve talked about SNPs (single nucleotide polymorphisms) before on the blog. These are mutations in single bases along the DNA molecule. Because it has been found that some SNPs are associated with particular diseases, geneticists scan genomes to identify SNPs that may either explain a disease or at least identify individuals that may be at risk for a disease. As described in a recent report in Reuters, one unintended consequence of these genome scans has been the identification of incest. As many of you know, the development of abnormalities in offspring is more common in incestuous (i.e., mating with a close relative–how “close” is “close” varies by culture)  matings. Because closely related individuals share a greater proportion of their genes, the chances are greater that deleterious recessive genes (genes that are only expressed when an individual has two copies, one from either parent) will pair up in their offspring and cause problems.

Although this new information of course has important legal implications, in most cases the physicians were already aware of the incestuous relationship.


Schaaf, C.P., Scott, D.A., Wiszniewska, J., Beaudet, A.L. (2011). Identification of incestuous parental relationships by SNP-based DNA microarrays. Lancet 377: 555-556.