Genetics and Dog Breeds

     

    Humans have placed artificial selective pressures on dogs for centuries. People have bred them for their temperament, size, and other physical features. These selections have made the dog breeds we know today. I chose an article written by Jill Adams that was published in Nature in 2008. The article highlights a variety of studies performed by researchers about the genetic factors involved in dog breeding. 

    Adams delves into the possible deleterious effects of dog breeding for specific physical characteristics. I found this to be particularly interesting because many brachycephalic dog breeds experience difficulties breathing. While the breathing difficulty is not a deleterious genetic defect, Adams mentions that some of the effects may not be known and that some have affected the mitochondrial genome in many dog breeds. 

Bottlenecked: Greenland's Inuit Population

      Genetic variation within a species' population is important to its overall health and survival. The article I came across was recently published in the Journal Genetics and discusses the effect of bottle-necking on a populations genetic variation. More specifically it looks into the Inuit population of Greenland and the effect bottle-necking has on deleterious, or harmful, genetic variations. For more insight into deleterious genetic variation you can take a look at this article by Kirk Lohmueller, who goes into detail about this phenomenon and its distribution in human populations.

       As for the original article the researchers found that the Inuit population did see a slight increase in deleterious alleles. They also determined the Inuit population had a much higher genetic load compared to other human populations who have experienced less bottle-necking. Genetic load refers to the difference between the fitness of optimal and observed genotypes in a population. This information gives insight into how the genetics of populations are negatively impacted by bottle-necking. These articles are in regards to human populations but this could be extrapolated onto other species. It seems to me that this is something that may help us in future wildlife conservation efforts.

Paternal Genes Exhibit More Dominance in Mammels

A study on laboratory mice from the University of North Carolina’s School of Medicine finds that mammals tend to exhibit more of their father’s DNA. Even though genes are inherited equally from both the mother and the father, the expression is found to be more dominant in paternal genes.

The study propagated three diverse inbred strains of mice together. The hybrid offspring were then examined to determine the level of gene expression exhibited from each parent. The study observed that genes inherited from the father were expressed in a larger amount than maternal genes.

This finding is important because deleterious mutations will have a much larger effect if inherited from the father than from the mother, as they will be expressed in a much greater amount. In the words of Fernando Pardo-Manuel de Villena, author of the study paper, “This is an exceptional new research finding that opens the door to an entirely new area of exploration in human genetics.”

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