Stage 1

Stage 1 of research focused on working with Embark raw data on 440 dogs from 24 different breeds using Genome-Wide Association Study - GWAS

GWAS is a statistical analysis technique that involves scanning markers across a full set of DNA to find a
genetic variant (mutation) associated with a specific trait. The geneticists look to identify an association
between genotypes at a particular marker/s and phenotypes observed with dogs involved in the research.
They search for markers where a given allele seems more prevalent in cases of dogs with full whiteheads
(white over both eyes) than control dogs with no white and no known white in the breed or line of dogs
within that breed.

In order to avoid false positive associations the testing uses a technique called Linear Mixed Models - LMM - which helps account for genetic relatedness. This is important information since there will be distinctive genetic markers found in different breed populations, related breeds and within related family lines.

Prof. Yuri Tani Utsunomiya DVM, MSc, PhD and Rafaela Beatriz Pintor Torrecilha DVM, MSc, PhD,
kindly offered their services to search for the genetic marker/s for the canine Whitehead trait. Their research uses the "Illumina CanineHD Array" chip, which is the same array that Embark uses for their testing.

The first stage of this research was successful in mapping a possible genomic loci candidate.
SNP array can help in locating a chromosomal segment containing the variant, but will not provide
sufficient evidence to identify the precise mutation.
Identifying the mutation will need to be achieved using whole genome sequences focusing on the loci candidate.