What is a Blue Merle

Blue merle is a coat colour pattern in dogs that gives off a marbled or mottled look. It’s usually seen in breeds like Border Collies, Australian Shepherds, Shetland Sheepdogs (Shelties), and Cardigan Welsh Corgis.

The term "blue" refers to the dilution of black pigment, resulting in a greyish or bluish colour, and "merle" describes the marbling effect created by patches or streaks of a darker colour on a lighter base.

This colorant mix is caused by a genetic combination of the merle gene and the dilution gene.

The merle gene creates irregular patches of colour, and the dilution gene affects the strength of the pigments resulting in a blue or grey base coat and patches of darker blue, black, or grey.

The patterns and distribution of colours can vary greatly among blue merle dogs and can look vasgtly different from each other.

NOW, while blue merle is a beautiful colouring for a dog’s coat, it’s not just an aesthetic trait, it can also affect their health.

When two merle-carrying dogs are bred together their offspring can present in double merle or homozygous form. This breeding practice should be avoided at all costs as common health issues associated with this breeding partnership can include vision and hearing problems, such as partial or complete deafness and blindness.

Responsible breeding practices should minimise the risk of these associated health conditions.