Flashcards in Chapter 3 Deck (56)
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1
1) When an F1 hybrid does not resemble either pure breeding parents
2) Intermediate phenotype where both parental alleles contribute to the phenotype
3) 1:2:1 phenotypic ratio exactly reflects the genotype can ratio
4) recessive may not be expressing a viable protein (snap dragons)
Incomplete dominance
2
1) Both traits show up equally in the heterozygotes phenotype in the F1 cross (spotted dotted lentils) 2)1:2:1 in the F2 generation 3) blood group alleles (a and b sugars)
Codominant
3
Novel phenotype determined by 2 or more genes, or from interactions between genes and the environment (green lentils) 9:3:3:1
Multifactorial
4
A given gene may have more than two alleles.
Sugar adding enzyme in blood
Multiple alleles
5
Alleles are listed in order from most to least dominant
Dominance series
6
Chance alterations of the genetic material that are spontaneous in nature
Mutations
7
Percentage of the total number of gene copies
Allele frequency
8
The most common alleles of each gene In a population, or if present, at a frequency of greater than 1%, often designated +
Wild type
9
Rare allele
Mutant allele
10
A gene with only one common wild type allele,
Agouti,
More than 99% frequency
Monomorphic
11
Some genes have more than one common allele,
ABO blood type system
Polymorphic
12
High frequency alleles of a polymorphic gene,
ABO blood type system
Common variants
13
When a single gene determines a # of distinct and seemingly unrelated characteristics,
Mutations can influence multiple biochemical processes
Plieotropy
14
An allele that negatively affects the survival of a Homozygote, 1:2 phenotypic ratio indicates a missing genotype
Recessive lethal alleles
15
Extension: Incomplete dominance or codominance,
On crossing F1, Phenotypes are 1:2:1,
Unlike either Homozygote
Extension to complete dominance
16
Extension: multiple alleles
Multiplicity of Phenotypes
Series of 3:1 ratios
Extension to two alleles
17
Extension: recessive lethal alleles
2:1 instead of 3:1
Heterozygotes survive but may have visible Phenotypes
Extension to all alleles are equally viable
18
Extension: Plieotropy,
One gene affects Several traits, affected several ways depending on dominance relationships, Different ratios
Extension to one gene determines one trait
19
Two genes working in tandem To produce purple sweet pea flowers, a dominant allele of each gene (producing white flowers) must be present (in opposite parents) to produce that color
9:7 in the F2; A-B- is the only purple phenotype
Complementary gene action
20
A gene interaction in which the effects of an allele at one gene hide the effects of alleles at another gene. Can be either dominant or recessive.
Epistasis
21
Homozygous for a recessive allele of the second gene is required to hide the effects of another gene to cause a masking phenomenon
9:3:4 in Chocolate labs
Recessive Epistasis
22
Dark color in dog coats
Eumelanin
23
Light color of dog coats
Pheomelanin
24
Epistasis when the dominant allele of one gene hides the effects of another gene
Chickens
Dominant Epistasis
25
15:1
Specify nearly identical proteins that perform the same function
Redundant gene action
26
One dominant allele of each of 2 genes is Necessary to produce phenotype
9:7
Sweet pea flowers
Complementarity
27
Homozygous recessive of one gene masks both alleles of another
9:3:4
Labrador retriever coat color
Recessive Epistasis
28
Dominant allele of one gene masks the effects of both alleles of another gene 12:3:1
Summer squash color
Dominant Epistasis 1
29
Dominant allele of one gene hides effects of dominant allele of other gene
13:3
Chicken feathers
Dominant Epistasis 2
30
