In a path-breaking study on human genetics by Netherlands scientists (led by Anfred Kayser of the Erasmus University Medical Center Rotterdam), scientists are now able to predict with a stupendous 90 percent accuracy the eye color of a person - just by analysing a person's DNA from only 6 different positions of the genome.
Human eye colour, which is determined by the extent and type of pigmentation on the eye's iris, is what geneticists call a 'complex trait'. This means that several genes control, which colour the eyes, will ultimately have.
Over the past decades a number of such 'eye-colour genes' have been identified, and people with different eye colour, will have a different DNA sequence at certain points in these genes.
Such differences are known as single nucleotide polymorphisms (SNPs).
The researchers analysed the DNA of over 6000 Dutch people whose eye colour had been scored. They determined the sequence at 37 SNPs in 8 eye colour genes for each of these and found that the eye colour of a given individual can be predicted with over 90 percent confidence already with the best 6 SNPs from 6 genes, as long as the persons's eyes are blue or brown.
For the intermediate colour, shown by about 10 percent of the people tested, the accuracy is lower at about 75 percent.
The study has two-fold implications-firstly, it is a proof-of-principle that complex traits can be predicted from the genome sequence alone, provided that genes with strong effects on the trait exist and are known. This can have implications for predicting disease risks based on DNA, before the disease breaks out.
Also, the findings have direct relevance in the forensic sector.
The study is published in the journal Current Biology, a Cell Press publication.