Genes A and B are 10 map units apart and genes B and C are 20 map units apart, with gene B located between genes A and C. What would be the expected amount of double crossovers for a trihybrid test cross

2% of the progeny will be double crossovers for the trihybrid test cross

Explanation:  

By knowing the positions of genes, we can estimate the distances in MU between them per region.

A10MUB20MUC---

             Region I                      Region II  

We can estimate the recombination frequencies by dividing each distance by 100.

•recombination frequency of A-B region = 10MU / 100 = 0.10

•recombination frequency of B-C region = 20MU / 100 = 0.20

Now that we know the recombination frequencies in each region, we can calculate the expected double recombinant frequency, EDRF, like this:

EDRF = recombination frequency in region I x recombination frequency in region II.

EDRF = 0.10 x 0.20 = 0.02        

2% of the progeny will be double crossovers for the trihybrid test cross

as resources become scarce because of population growth, the growth decreases after few years due to lack of resources and food.

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation: