• Question: Why when puppies are born they don't all look the same and have the same colour fur? Example one puppy could be white with dark black spots but another puppy could be white with faded black spots

    Asked by 798genp37 to Remsha, Kieran on 7 Nov 2018.
    • Photo: Kieran

      Kieran answered on 7 Nov 2018: last edited 7 Nov 2018 12:04 pm

      Good question – this is down to genetics. Your puppies may have the same parents, but so do you and your siblings. DIfferences in colour (called the phenotype) can result from changes in the DNA (called the genotype) which occurs during fertilisation. Sometimes when cells divide, the pieces of DNA can change in location on a chromosome – this is called recombination. This also can explain differences between individuals.

    • Photo: Remsha Afzal

      Remsha Afzal answered on 7 Nov 2018:

      Great question! The answer comes in two parts: genetics and/or dog anatomy/behavior.

      If the parents of the puppies are purebreds or are in general similar in appearance, size and behavior, then the puppies will also look similar. In sciency terms there is less genetic variation there. For example, if you have a litter of Golden Retriever pups, you shouldn’t really expect a black dog or one with spots or colored patches. Its like if you make cream of chicken soup, you don’t expect to find vegetables in there. But if you have parents of mixed breeds, the puppies can end up looking different from each other because of recombination like Kieran mentioned.

      In dogs, however, there is another reason why the pups in a litter may not look alike apart from the genetic recombination. That is because the puppies in the litter may not have the same fathers! Dogs are a polygamous species (meaning they tend to mate with different partners during mating season) and their reproductive systems work in a different way. Female dogs produce and release a number of eggs at the same time, which is why they have litters of pups rather than one at a time. So because one female has several eggs, each egg can be fertilized by sperm coming from more than one male dog.

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