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Question

Genetics? ?? ?
i have a set of genetics word problems and i'm really stuck on this one. any help will be great! thanks

39) two pigs whose tails are exactly 25 cm in length are bred over 10 years and they produce 96 piglets with the following tail lengths, 6 pihlts at 15 cm, 25 at 20 cm, 37 at 25cm, 23 at 30 cm, and 5 at 35cm.
---A) how many pairs of genes are regulating the tail length character?
---B) what offspring phenotypes would you expect from a mating between a 15 cm and a 30 cm pig

Answer 1

This process occurs through the phenomenon of additive alleles.

When additive alleles control a trait, then we can use the ratio of the F2 generation to figure out the number of gene pairs involved. The way to figure this out is to use the 2n+1= method. N would be the number of gene pairs which is the number you are trying ot figure out, where the = would be the number of phenotypically different groups you have. Because you have 5 phenotypically different groups, 2n=1=5, therefore this only involves 2 gene pairs. Each group also, note, has a separation of 5 cm between each.

B. A mating of a 15 cm pig and a 30 cm pig would result in the following:

There are two gene pairs involved therefore you would do a cross between the following gametes to get it.

Gametes of 30 cm
AB
Ab
aB

Gamete of 15 cm
ab

Do the cross and you should get your answer. Remember for every recessive gene you have a 5 cm difference in height.

Good luck and hope this helps!

Answer 2

Look at the ratios of the number of piglets with each tail length, 1:4:6:4:1, knowing that you should be able to work it out.

Answer 3

Anyone answering that question correctly should get the noble prize Oink Oink

Answer 4

been a long time since i took biology have you tried your fellow classmates or perhaps the homework helper website.