When it comes to the rate of survival, usually it is the more dominant, larger, and bigger animals to out survive their weaker . In the case of the Soay sheep in the Scottish island, it's actually the other way around. After being studied for the past 20 years without any intervention from scientists, researchers have been tracking the herds of these animals, noting their coat color, size, and reproduction rates and found that the recessive gene sheep are surviving better than their dominant counterparts.
On this island, there are two types of sheep - light coats and dark coats. Since the sheep with the dark coats are born with the dominant trait, they also are born with bigger, stronger bodies. However, when born with the dark coat, they also retain the gene that leads to low reproductive rates and survival rates among juvenile sheep.
To have a dominant, dark coated offspring means that at least one of the parents must have the dominant trait as well. Having the dark coat gene will override any recessive gene present, in this case the light coat color, and make the offspring heterozygous, meaning that they are born with both traits but only the
dominant phenotypic trait shows. In order to produce a light coat sheep, both parents must be light coat or be heterozygous for the gene. It was also studied that sheep being homozygous, or having two copies of the same gene, have the lowest rate or reproduction, heterozygous dark sheep had a medium rate of reproduction, and homozygous recessive sheep had the highest rates.
Evidently, it pays off to have the recessive gene on this island of sheep, however the ratio between the light and dark coat sheep is not what is expected. The current ratio is 3 dark sheep to 1 light sheep, which follows along with the Punnet's ratio of 3 dominant:1 recessive between heterozygous matings. But after learning that the light coat sheep have better rates of survival, I believed that this ratio would actually favor the light sheep rather than the dominant dark sheep. This can be seen as another example proving the 3:1 ratio, despite the reproductive rates of the animals.
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