Merle - the ‘cryptic colour gene’

Merle - the ‘cryptic colour gene’

Aim

To use the results of analyses of the merle gene in individuals of different breeds as a basis for developing breed specific recommendations for DNA testing. It is also possible to contribute your own ideas for analyses to the project.

Background

Merle is a pattern rather than a colour and is caused by a mutation in the dog's genome. The trait occurs in several dog breeds. The genetic basis of merle is known and consists of an insertion of a variable number of base pairs in PMEL17. Today, it is believed that there are at least five different gene variants/alleles of merle. These five can be combined into 15 different genotypes.

The inheritance of the merle gene has been shown to be unstable. During DNA copying and cell division, the merle gene (M) can in some cases be transformed into, for example, atypical or cryptic merle. A merle ‘coloured’ dog often attracts attention but the trait should not be ‘duplicated’ as dogs that inherit the trait from both parents risk serious defects, such as deafness and eye problems.

It is therefore important for breeders (of breeds where the gene occurs) to have their stud dogs DNA tested for the presence or absence of the merle gene.

Project description

The project is laboratory based and involves DNA extraction (robot), PCR and fragment analysis (3500) of buccal swabs. You will work with genetic markers that have already been developed and evaluated. The dogs are from different breeds where merle is present. Photographs are also available for most of the dogs. You will then analyse the fragment lengths and calculate the frequencies of the different length variants/alleles in different breeds.

Buccal swabs are collected so that the laboratory part of the project can begin, but it is also possible to contact dog owners and carry out your own, supplementary collection if desired.

Specifications

Some laboratory experience is an advantage.