|MadSci Network: Genetics|
Well, with humans, inbreeding is not good at all. Through the ages humans have come to realize that inbreding causes detrimental effects. This is mainly due to the fact that we have two copies of each gene in our cells. If a brother and a sister are heterozygous (in this case heterozygous will mean that we have one good allele and one bad allele) for a particular gene they will probably live healthy lives with respect to those genes. Remember an allele is an alternate form of a gene. However, if the brother and sister (or any close relatives) were to mate, there is a good chance that their offspring would contain 2 copies of a detrimental gene that may exist within their family blood line. So, when close relatives mate they increase the chances that a particular 'bad' allele will appear twice within their cells. Since, there is no 'good' copy of an allele for the cells to rely on these alleles may end up causing a disease or disorder for the organism in question. Pure-breed pets are full of disorders. Many pure-breed dogs have bad hip joints. The term "pure-breed" doesn't say anything about how many detrimental mutations that breed has. Pure-breed animals are only pure with respect to the characteristics the breeder has chosen. For example, if you want a dog with long hair you may look for a dog that has been purely (soley) breed for having long hair, nothing else matters. The sad thing is that a dog may be a pure-breed for a set of features but end up having disorders or 'bad' features because the breeder was not concerned with them. Some dogs and cats continually 'cry' because they were breed to have 'flat' faces. These flat faces squish the tear glands to the point that it appears that the animals are crying. -Hope this Helps -Mike
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