Topic 7: Genotype, phenotype, and inheritance

Question 1

Define genotype and phenotype

Answer 1

Genotype: gene on chromosomes in nucleus
Proteins: in cytoplasm
A phenotype is the observable characteristics of an individual resultsing from the interaction of its genotype with the environment

Question 2

Define gene and allele

Answer 2

Allele: versions of the same gene at the same position on a chromosome. Each individual has 2 alleles of a gene

Question 3

Explain and describe the Mendelian autosomal and se-linked inheritance patterns

Answer 3

Autosomal: recessive or dominant
Sex-linked: gene on X or y chromosome.
X linked recessive OR X-linked dominant or Y linked

Question 4

Describe mitochondrial inheritance

Answer 4

When genes are inherited through the maternal line

Question 5

What is polygenic and multifactorial inheritance

Answer 5

Factors inherited that are a combination of inheritance and environmental factors

Question 6

Explain modes of inheritance

Answer 6

Dominant: determines phenotype in heterozygotes
Recessive: non-dominant allele in heterozygote

Question 7

Explain penetrance and expressivity

Answer 7

Penetrance describes whether there is clinical expression of a phenotype in a person. eg: percentage of people with a genotype that show a symptom
Expressivity describes the difference in clinical presentation between two people with the same genotype. eg: severity of the disease in different people