Gene Interactions

Question 1

Incomplete Dominance

Answer 1

• Neither allele is completely dominant over the other.
• Both alleles are expressed/have an effect.
• Produces a new phenotype

Question 2

Co-domiance

Answer 2

• Neither allele is completely dominant to the other
• Either allele can be expressed
• Both phenotypes are seen separately

Question 3

Epistatic effects

Answer 3

• Where one gene affects the expression of another gene

Question 4

Sex-linkage

Answer 4

• This is when genes are carried on the sex chromosomes X or Y

Question 5

Sex-influenced

Answer 5

• The phenotype depends on the gender of the animal even though the gene controlling the characteristic is not on the sex chromosome.
• It’s influenced by sex hormones

Question 6

Multiple Alleles

Answer 6

• This is where three or more alternative alleles of a single gene are possible
• But only two are present in an individual organism

Question 7

Lethal Alleles

Answer 7

• These are pairs of homozygous alleles that cause an animal to die if they have them
• Lethal Alleles arise when a mutation to a normal allele disrupts the function of an essential gene
• Without this essential gene the animal will die
• Lethal Alleles can be dominant or recessive