Healthy dogs

"One group of scientists set out to answer this question with the CanMap Project. They created a huge genetic map of canine DNA. The scientists gathered this DNA from 80 different dog breeds as well as wolves, jackals, and even feral African village dogs. We wouldn’t want to cuddle with some of those breeds....

Short segments of genes from a distant dog relative, the gray wolf, were found in every sample of the dogs’ genetic information. However, the nucleotides that make dogs look different were only found in a few areas of the DNA. These reflect the areas that have changed in the centuries since people started breeding dogs for different traits, creating many different breeds of dog in the process.

In humans, our diversity and nucleotide puzzle pieces work differently. Instead of human diversity arising from a few different areas on the gene, the way we look is regulated by hundreds of different weak genes that interact to make us unique! Dogs may have fewer areas of diversity compared to humans because of what scientists call a gene bottleneck....

Genes from this Great Dane and Chihuahua mix are similar, even though they look very different. Wikimedia - Ellen Levy Finch

So are Great Danes and Chihuahuas pretty much the same? Yes and no. Just by looking at these dogs, you can tell that they are very different, but that’s because of humans breeding them to look like that. Scientists found that only a small number of genes actually account for different phenotypes. So only a few very powerful gene locations lead to doggie diversity, even though dog breeds look so different!"