Scientists have identified a gene that determines canine coat color, and the discovery could help explain why humans come in different weights and vary in our abilities to cope with stress, according to HealthDay News Friday.(File Photo)

    BEIJING, Nov. 2 (Xinhuanet) -- Scientists have identified a gene that determines canine coat color, and the discovery could help explain why humans come in different weights and vary in our abilities to cope with stress, according to HealthDay News Friday.

    The study, published in the Nov. 2 issue of Science, was carried out by researchers from the Stanford University School of Medicine.

    They analyzed DNA samples from hundreds of dogs and pinpointed a gene.

    The gene belongs to the large family of defensin genes, which may play a role in fighting infections.     

    One version of the gene produces yellow dogs, while a mutant version produces black dogs, the researchers found.

    The beta-defensin gene is part of a large and variable family of defensin genes. Humans can have between 40 and 50 defensin genes, and dogs can carry up to 46 of these genes.

    "The most important observation that stems from the paper is that in trying to understand what defensins really do, we've been looking under a lamppost based on the way in which the gene family was named," research team leader Dr. Greg Barsh said.

    "In fact, we really have very little evidence that defensins do much in terms of defending. The genetic approach is more agnostic and suggests that defensins have additional or alternative functions outside the immune system."

    Barsh said one of his lab's immediate plans is to learn more about what human defensins do and whether they may be useful in helping develop new drugs.

(Agencies)