A geneticist determines that long hair length in mink is dominant over short hair (recessive). his friend breeds mink in captivity with long hair esp for the fur inducstry and has received permission from the Kansas Department of Wildlife and Parks to trap 5 wild mink to add to his breeding stock to reduce effects of inbreeding within his colony, but he wants to otherwise maintain production of all long-haired mink. 4 of the 5 wild mink have long hair, the 5th has short hair. If he has room to house only 2 more mink as breeding stock during the subsequent 5-year period, explain how his geneticist friend should advise him to procced in conducting a test cross to detemine which (if any) of the wild-trapped mink he should retain for his breeding project for the next 5 years. (I am assuming mink breed year round and prodcue 5 litters per year)
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The first thing you need to do is determine the genotype of the captive minks. It says that he wants to "maintain production of all long-haired minks". This suggests to me that in his current mink population every offspring is long-haired. Now let's think about the genotype/phenotype relationship. We know from the statement that long hair (L) is dominant over short hair (l); this means that to have a long-hair phenotype (a long haired animal) we only need one dominant gene (L). Therefore minks with genes LL and Ll will be longhaired and ll will be shorthaired. Mating LL with LL will give us only LL offspring, ll x ll will give only ll animals, whereas LL x ll, LL x Ll, and Li x ll will give us a mix of short and long haired offspring (LL, Ll or ll). The predicted ratio of each of these combinations can be figured out using the punnet square technique, and will be important to us when we determine which wild minks to keep in captivity. So knowing all that, and knowing that in captivity we only get long-haired offspring 100% of the time, what genotype (ll, Ll, or LL) are the captive animals?
The statement tells us we have 5 wild minks, 4 with long hair and 1 with short hair. ...
In this solution I describe the relationship between genotypes and phenotypes and the punnet square method to answer the questions related to mink breeding.