Self-Check 2

Question 1

A person’s _____ is their combination of alleles. When a person has two copies of the same allele for a Mendelian trait we call them ____.

Answer 1

Genotype and homozygous.

Question 2

X-linked traits are never passed from a male parent to a male offspring.

Answer 2

True.

Question 3

With autosomal recessive traits, heterozygotes are:

Answer 3

Carriers.

Question 4

With an autosomal dominant trait, it is possible for two affected parents to have unaffected offspring.

Answer 4

True.

Question 5

In a pedigree diagram, an affected female is represented by a:

Answer 5

Shaded Circle.

Question 6

According to the readings, why might gene carrier screening be a good idea?

Answer 6

• most carriers of disease-causing recessive alleles are unaware of their status
  -most humans carry disease-causing recessive alleles
  -It reduces death and disease caused by recessive alleles

Question 7

According to the readings, why might gene carrier screening be problematic?

Answer 7

• doctors and patients may not understand how positive results relate to actual disease risk
  -it involves making quality of life judgements before a person is born
  -it may promote discrimination against people with genetic conditions and their families
  -people who undergo screening are often unprepared for a positive result

Question 8

Heritability is an estimate of the:

Answer 8

genetic contribution to a trait

Question 9

A polygenic risk score is

Answer 9

• a measure of genetic risk for a complex disease
  -a way to enhance non-genetic risk prediction models for disease

Question 10

What are some limitations of polygenic risk scores highlighted in the readings?

Answer 10

• lack of diversity in reference samples
• limited ability to predict disease
  -potential to cause psychological distress
  -potential to be misinterpreted