The first child of this couple was Rh-negative. What is the chance that the second child of this cou

1.) The first child of this couple was Rh-negative. What is the chance that the second child of this couple be a girl and be Rh-negative? Show your work. 3 marks

HINT: 0.50 is incorrect. Do you remember the Fundamental Counting Principle from your Mathematics courses?

In general, if you have n choices for a first case and m choices for a second case, you have n X m choices for both cases happening. The two cases must be independent of each other; either one does not influence the other in any way.

2.) Nomenclature for writing alleles on a homologous chromosome pair

The phrase DEP/dep means the first three letters, DEP, represent the alleles that will appear, in this order, on the first homologous chromosome. The “/” signifies the following alleles, dep, will appear on the second homologous chromosome (also in the stated order).  It is to be assumed that the genes will appear at the same location on both the two homologous chromosomes.

A student wrote the male genotype as DEP/dep. Do you agree? Explain. 2 marks

HINT:    
Distance from the centromere and map units apart from other genes are factors in _______.
Correct: the probability of crossing over.

3.) The sperm chromosome maps are more likely to be DeP than DEP. Explain. 2 marks

HINT: Again the location of the alleles on the chromosome is important. The farther apart, and the greater the distance from the centromere, then the higher the cross-over rate.