4. Extending Mendelian Genetics

Question 1

What is incomplete dominance?

Answer 1

when the phenotype of a heterozygote is a blended mix of both alleles

Question 2

What is codominance?

Answer 2

two alleles are both expressed but are not blended

Question 3

What are pleiotropic effects?

Answer 3

a gene whose expression alters many different, seemingly unrelated aspects of the organisms total phenotype

Question 4

What is polygenism?

Answer 4

complex traits that are influenced by many different genes

Question 5

What is penetrance?

Answer 5

decribes the likelihood that a person with a given genotype will express that expected phenotype

Question 6

What is epistasis?

Answer 6

refers to a situation where expression of alleles for one gene is dependent on a different gene

Question 7

What are recessive lethal alleles?

Answer 7

mutant alleles that can cause death of an organism when present in a homozygous manner

Question 8

What are sex-linked traits?

Answer 8

traits that are determined by genes on either the X or Y chromosome