Improved eye- and skin-color prediction based on 8 SNPs

Area of Science:

• Human genetics
• Phenotypic prediction
• Forensic genetics

Background:

• Predicting human eye and skin color is crucial for forensic and anthropological studies.
• Existing genetic prediction systems, like the 7-plex system, have limitations in precision and detailed phenotypic descriptions.

Purpose of the Study:

• To enhance the precision of the 7-plex system for predicting eye and skin color.
• To develop a more detailed and accurate phenotypic description model using an expanded set of single nucleotide polymorphisms (SNPs).

Main Methods:

• An eighth SNP, rs12896399 (SLC24A4), was analyzed and added to the existing 7-plex system, creating an 8-plex system.
• Genotype interpretation guidelines were revised, and the system was trained on an 803-sample dataset.
• The 8-plex system was validated on a separate 212-sample test set.

Main Results:

• The 8-plex system significantly improved the prediction of brown, green, and blue eye colors (P=6.98e-15).
• Eye color prediction error rate was approximately 5% in the test set.
• Skin color prediction demonstrated high accuracy with a 1% error rate in the training set and no error in the test set.

Conclusions:

• The new 8-plex system offers substantial improvements over the previous 7-plex version for predicting eye and skin color.
• The enhanced system provides more precise predictions, including the ability to distinguish blue eye and light skin colors.