8.3 Inheritance

Question 1

When is the mode or inheritance autosomal recessive?

Answer 1

When the trait skips generations and is not sex-linked

Question 2

When is the mode of inheritance autosomal dominant?

Answer 2

When the trait does not skip generations and is not sex-linked

Question 3

When is the mode of inheritance sex-linked recessive?

Answer 3

When the trait skips generations and is on one of the sex chromosomes

Question 4

When is the mode of inheritance sex-linked dominant?

Answer 4

When the trait does not ski generations and is on one of the sex chromosomes

Question 5

How can you tell if a trait is sex linked?

Answer 5

If there are more males than females with the trait, and if all the sons of an effected female are also effected.

Question 6

What is the phenotype ratio for a cross between a female with a homozygous dominant genotype and a male with a recessive genotype (sex-linked)

Answer 6

2/4 dominant phenotype females: 2/4 dominant phenotype males

Question 7

What is a carrier?

Answer 7

Someone who has a normal phenotype because the normal allele produces enough functioning proteins

Question 8

In semi-dominant inheritance, what happens when someone has 2 non-functioning copies of a gene?

Answer 8

full-blown disorder

Question 9

What do recessive alleles often code for?

Answer 9

non-functioning proteins or no proteins at all