Study Guide 8.3

Question 1

What are autosomal recessive and autosomal dominant?

Answer 1

Autosomal recessive: 2 copies of the disease must be present.

Autosomal dominant: Only one copy of the disease needs to be present.

Question 2

What is y-linked?

Answer 2

A trait passed to the son(s) by the father and the father only by the Y chromosome.

Question 3

What are sex-linked recessive and sex-linked dominant?

Answer 3

Sex-linked recessive: The parents can be heterozygous for the recssive trait and pass the recessive traits to their offspring who will have the disease. The parents either need to have the disease (mother homozygous and father has the recessive allele) and/or be a carrier of the disease (heteroygous).

Sex-linked dominant: If they have the dominant allele, they have the disease, even if they have one recessive allele. There are no carriers. If there is one dominant allele, then they have the disease/disorder. (I’m so sorry.)

Question 4

Please explain how to tell the differences between autosomal recessive and autosomal dominant on a pedigree.

Answer 4

Autosomal recessive skips generations while autosomal dominant does not. Also, both parents need to have the recessive allele and both pass that on to their offspring for autosomal recessive. In autosomal dominant, only one parent needs to pass on the dominant allele. The pedigrees show this. In autosomal recessive, the parents may not have the disease/disorder, but some of the offspring may. In autosomal dominant, both of the parents may have the disease/disorder, but some of the offspring may not.

Question 5

Please explain how to tell the differences between sex-linked recessive and sex-linked dominant on a pedigree.

Answer 5

Sex-linked recessive is shown on a pedigree to be mostly in males. Also, the one with the disorder/disease must have a recessive allele from both parents. This one also skips generations. Sex-linked dominant means the person only needs one dominant allele to have the disorder/disease. This one doesn’t skip generations, and this one doesn’t affect males more than females.

Question 6

Please name disorders and mode of inheritance they are connected to.

Question 7

What is the term for the definition: A trait passed to the son(s) by the father and the father only by the Y chromosome?

Answer 7

Y-linked.