Question

1.Swyer syndrome is a Y-linked genetic disorder.

What are the chances that any of their daughters will have Swyer syndrome? and What are the chances that any of their sons will have it?

2.If a mutation causes a permanent change in the DNA sequence, how is it that most mutations are “silent” mutations

3.Suppose a young woman is exposed to a chemical mutagen and some permanent changes arise in the DNA (mutations) of some of her germ line cells. Will those mutations be passed down to her children? Why or why not

4. humans, attached earlobes (A) are dominant to free earlobes (a). Suppose a couple who are both heterozygous for this trait have a child. Tell me
⦁   the phenotype of the parents:
⦁   the genotype of the parents:
⦁   the likelihood (or chance) that their child will have free earlobes:

Answer 1

Answer =

1.Swyer syndrome is a Y-linked genetic disorder.

the chances that any of their daughters will have Swyer syndrome = 0%

and  the chances that any of their sons will have it = 100 %

Explanation = Swyer syndrome is a Y-linked genetic disorder.the SRY genes which are present on Y chromosome undergoes mutation to cause Swyer syndrome.

it means that it can be inherited from male because Y chromosomes are only present in male.

phenotype = male (Swyer syndrome) X Female (normal)

genotypes = XY X   XX

offsprings:

	X	Y
X	XX ( normal daughter)	XY( swyer syndrome son)
X	XX ( normal daughter)	XY( swyer syndrome son)

therefore : all daughters are normal = 100% daughters are normal.

any of daughter has syndrome = 0%

all sons are affecetd = 100 %