lecture 9

Question 1

explain basis of gene ineteractions and how it affects phenotypic variation

what ratio to expect in a dihybrid cross

Answer 1

• 2+ genes influencing same trait; influence the outcome of a signle trait
• 9:3:3:1 ratio; if two genes affect the same trait the ratio is skewed

Question 2

Explain complementary genes

Answer 2

• 9:7 ratio
• occurs when 2 or more genes work tgt to produce a particular trait
• discovered Batesone and Punnett
• fully reccessive masks a single dominant allele

Question 3

Explain redundancy

Answer 3

• 15:1 ratio
• George shull
• atleast the presence of one dominant allele produces the WT phenotype

Question 4

Explain recessive epistasis

define epistatic and hypostatic

Answer 4

• 9:3:4
• occurs when the effect of an allele hides the effect of an allel on another gene and expresses its own phenotype instead
• epstatic locus of homo recessive prevent the expression of hypostatic locus phenotype

Question 5

Explain dominant epistasis

Answer 5

• 12:3:1
• when the dominant allel is epistatic to a recessive allele making it hypostatic

Question 6

how to solve for the mode of inheritance?

Answer 6

calculate the reduced ratio
1. (total # of F2/ total # of possible alleles)
2. divide each F2 class number with the calculated number and get ratio