Question
Question 2.3 only please and explain. thanks
Coat color variation in mammals has long served as one of most fruitful examples of genetics, with over 120 loci and 800 alleles affecting coat color described mice alone, For this question, we will consider the adaptive from in that accompanied the movement of mice from the forest to the dark to light coat coloration species beach among two species of mouse. The ancestral species was darkly colored while the derived was more lightly mouse living on colored, with the selective pressures that come when you are a dark F1 individual lightly colored s The phenotypes of the two parental species, along with a representative and representatives from the F2 shown below. generation are Derived 00 2.1 (10 Assume that you only had the data shown above for the parental lines (ancestral and derived species) and the F1. What inferences would you make about the mode of inheritance for the overall (whole body) coat color? Support your inferences clearly ldo not just write the mode of inheritance, explain why you arrived at that answer] 2.2 (10) With the added data from the F2, what inferences might you make about the mode of inheritance for the overall (whole body) coat color? Support your inferences clearly ldo not just write the mode of inheritance, explain why you arrived at that answer Researchers performed genetic mapping experiments to locate genes involved in the determination of pigmentation and found two loci M (chromosome 1), and AGOUTI (chromosome 7 that both affect pigmentation. Each of these loci have two alleles, one associated with light coloration (the L allele) and one sociated with the dark coloration (the D allele). When the researchers analyzed the effect of the alleles at these two loci on cheek coloration, the following results were obtained. The y-axis of the graph is a measure of color where low numbers represent dark coloration and large numbers represent lighter coloration.
Explanation / Answer
It can be seen from the graph that appearance of light colored cheek colors in mice was more prevalant in mice with genotype either homozygous LL or heterozygous LD. Genotype DD gave no invidividuls with light cheeks and surprisingly, no individual with dark cheeks as well. This clearly suggests two facts:
1. The cheek color is inherited by means of two alleles, L and D where the blend of two alleles gives rise to slightly darker cheeks and homozyous LL give rise to a large number of light cheek mice.
2. Since no individual homozyous for DD alllele was seen, it infers that the homozyous DD allele must be lethal in nature for these mice. This might happen due to presence of any lethal allele neary D alle and its expression in homozyous condition in these mice. This is why a range of cheek colors from dark to light is seen in these mice whereas no mice with homozyogus DD genotype is seen.
Thus, the mode of inheritance for cheek color in these mice is autosomal in nature where D and L seem to be co-dominant in nature because L and D give rise to a little darker phenotype in heterozygous condition. However, absence of homozygous DD allelic combination clearly suggests that this combination might be lethal for the mice which requires futher experimental investigations.
