Lecture 3d: Genes of Variable Expressivity

Question 1

occur in a genome when a single base pair is added, deleted, or changed.

Answer 1

point mutation

Question 2

the degree to which a phenotype is expressed by individuals having a particular genotype.

Answer 2

expressivity

Question 3

Introns are supposed to be __, while the exons are __. The mutation must occur at the specific site at which intron splicing occurs: within non-coding sites in a gene, directly next to the location of the exon.

Answer 3

• removed
• expressed

Question 4

A single mutation simultaneously affects several traits
Example: __

Answer 4

• pleiotrophy
• Sickle cell anemia

Question 5

HbS HbA = __
HbS HbS = __
HbA HbA = __

Answer 5

• Sickle-cell trait
• Sickle-cell anemia
• Normal

Question 6

Another example of Pleiotrophy

Answer 6

phenylketonuria (PKU)

Question 7

Sickle cell disease is diagnosed by __.

Answer 7

hemoglobin electrophoresis

Question 8

This disorder is caused by a deficiency of the enzyme phenylalanine hydroxylase, which is necessary to convert the essential amino acid phenylalanine to tyrosine.

Answer 8

phenylketonuria (PKU)

Question 9

given genotype may or may not show phenotype

Answer 9

penetrance

Question 10

determines how much the trait affects or how many features of the trait appear in the person

Answer 10

expressivity

Question 11

refers to whether the gene is expressed or not. That is, it refers to how many people with the gene have the trait associated with the gene.

Answer 11

penetrance