Exceptions to Mendel's Rules

Question 2

dominance- Mendel’s dominance (complete dominance)

Answer 2

when genotype is heterozygous, one allele beats the other and is solely expressed (ex. BB- pigment, pigment-brown hair; Bb- pigment, no pigment- brown hair; bb- no pigment, no pigment- blonde hair- mutation that causes loss of function so is recessive)

Question 3

incomplete dominance

Answer 3

when the heterozygote has its own unique intermediate phenotype (ex. RR- red flowers, rr- white, Rr- pink), genotypic and phenotypic ratios are the same

Question 4

co-dominance

Answer 4

when heterozygote has both phenotypes simultaneously (ex. MM- M protein blood type, NN- N protein blood type, MN- both protein blood type)

Question 5

lack of function mutation

Answer 5

mutation negatively affects cell’s ability to make protein, therefore it is a loss of function mutation and will be recessive

Question 6

incomplete penetrance

Answer 6

when phenotype does not exactly correlate with genotype, caused by environmental factors and interactions between genes

Question 7

epistasis

Answer 7

genotype of one gene actually influences expression of another, epistatic gene controls/dominates/masks hypostatic gene

Question 8

recessive epistasis

Answer 8

gene controls when it is recessive (ex. BB and Bb make black, bb makes brown but EE and Ee allow deposition and ee prohibits deposition)

Question 9

dominant epistasis

Answer 9

1 gene suppresses other when it is dominant

Question 10

sex influenced characteristics

Answer 10

genetically inherited and influenced by sex but are not on X or Y chromosome, different penetrance in male vs female (ex. trait could be recessive in females and dominant in males)