An interesting biology question?

Question

A man and his wife wish to access IVF and PGD to have children who do not carry the man's X-linked recessive allele (assume his wife doesn't carry the allele).

Discuss the pros and cons of the following 2 options:

1. They should select only male embryos, discarding all female embryos.

2. All embryos could be genetically screened and embryos who carry teh normal alleles selected.

THANKS HEAPS...10 points best answer

Answer 1

well if its the X Chromosone then all the girl embros will be a carrier for the allele, because they have to get the fathers one X chromosone to be a girl. if its a boy embryo then it will get the fathers Y chromosome and there for not get the allele. so all the girls will have the allele from the father no matter what.

this is why

mother                          X      [ ]      X

Father         X --------XXgirl----- XX girl--------> dads Allele

                     Y            XY boy      XY Boy

the line represents the dads X linked allele

so  #1

Pro

you know all the male embryos will not have the allele

Con

there can be no daughter

#2

Pro

your positive none of the embrios you use have the allele

Con

you have to check all the embreos.

Answer 2

i want 10 points

Answer 3

Males would definitely not be either a carrier nor have the disease.  Females would be a carrier but not show the disease either.  So, as far as the next generation, neither boys nor girls would be afflicted.  However, only the girls could possibly lead to a direct line of the disease.  In this case the girl children have a 50% chance of producing a normal boy or girl (assuming the father doesn't have the trait), and a 25% of producing another girl carrier, and a 25% chance of producing an afflicted boy.  

Some of the argument for the pros and cons would have to be based on the allele frequency in the population.  If it is not a rare condition, then your views might have to change.

Answer 4

Give him ten points