The disorder where the grandfather and the grandchild are affected is related with the X chromosome and is called Sex linked or X linked disorder.
<h3><u>Explanation:</u></h3>
All the sex linked disorders are recessive in character i.e the normal allele is dominant over the mutated allele. In females, there are 2 X chromosomes, so the mutated allele is only expressed when there are both the mutated alleles, else its masked by the dominant normal allele. But in males, there's only one X chromosome, so if a mutated allele is present, it's readily expressed.
If the Grandfather is diseased, then he must have that mutated allele in X chromosome. Through reproduction, its received by the mother, but she is normal because the other allele received from grandmother was normal. But mother has one of the X chromosomes with mutated allele, which is received by the grandson who again becomes diseased.
So the disorder must be X linked disorder
Zippy Xylem. The xylem of a plant is the system of tubes and transport cells that circulates water and dissolved minerals.
A.) The phenotype is yellow, smooth
This is because (Y) yellow is dominant over (y) green. If an organism has a trait that is dominant, it will show up with no exceptions (YY, Yy, Ss, SS). Recessive traits on the other hand will only show up if both the maternal (Mom) and the paternal (Dad) copy given are both recessive (yy or ss).
b.) It depends on what the YySs plant is paired with. Will it be paired with another YySs, with YYSS, yyss, YySS, yySS, YYss...? For example, if it is paired with another YySs, make a punnett square.
