Chapter 5: 5.7 Inheritance of Autosomal Traits

Question 1

Define:

Autosomal traits

Answer 1

Ones that are not linked to the sex chromosomes
* Linked to the X sex chromosome

Question 2

Autosomal Dominant traits:

Prevalence

Answer 2

• Prevalent in the pedigree (more than half affected)
• Both males and females express the allele and can transmit it equally to sons and daughters

Question 3

Autosomal Dominant traits:

Trait prevalence

Answer 3

• Present in almost all generations
• Direct transmission through three generations is practically diagnostic of a dominant

Question 4

Autosomal Dominant traits:

What is the ratio of affected to unaffected children in affected families?

Answer 4

1:1

Question 5

True or False:

In autosomal dominant traits, parents can be carriers but not express the trait

Answer 5

False, if both parents are unaffected, all the children are unaffected

Question 6

Autosomal Recessive traits:

How can you tell if a trait is recessive?

Answer 6

Carriers have the recessive allele but don’t have the actual trait

Question 7

Autosomal Recessive traits:

Prevalence in family

Answer 7

Not very prevalent
* Not many have the trait or disease, not present in all generations

Question 8

Autosomal Recessive traits:

When two unaffected parents have a child that is affected by the trait, what is the ratio?

Answer 8

1 affected : 3 unaffected

Question 9

True or False:

All the children are affected if both parents are affected in autsomal recessive traits

Answer 9

True