Gene Interactions Flashcards Preview

BLGY1232 Introduction to genetics > Gene Interactions > Flashcards

Flashcards in Gene Interactions Deck (13):
1

What is epistasis?

An interaction between two different genes so that an allele of one of them interferes with or inhibits the phenotypic expression of the other

2

What is the gene which is inhibited/interfered with called?

Hypostatic

3

What is duplicate recessive epistasis?

When a dominant allele at either of two loci can mask the expression of recessive alleles at the two loci

4

How would we know whether two true breeding lines carry mutations in the same gene or different genes?

1. Collect a population of independently isolated mutants showing the same mutant trait
2. Cross them in pairwise combinations
3. How many crosses produce mutant offspring and how many crosses produce wildtype offspring?

5

What is a recessive lethal gene?

Absence of a gene product leads to death in homozygotes

6

What is a dominant lethal gene?

Both homoxygotes and heterozygotes carrying the allele will die.

7

What is a sex-linked lethal gene?

Homozygotes of the homogametic sex will die - heterozygotes will survive unless they inherit one copy of the lethal allele.

8

What is penetrance?

If individuals show the expected phenotype the gene is said to have complete pentrance 100%

9

What is expressivity?

A certain mutant gene may affect the phenotype of an organism to a different degree

10

What is variable expressivity?

Where the gene is expressed above a threshold you will see a phenotype, below you will not see the phenotype

11

What is complementation?

aaBB and AAbb, alleles a and A are complementary as are alleles B and b in double recessive epistasis

12

When does complementation occur?

When two strains of an organism with different homozygous recessive mutations that produce the same mutant phenotype produce offspring with the wild-type phenotype when mated or crossed.

13

What is a complementation group?

All mutants in the same gene