Variation and Inheritance

Question 1

Both alleles are expressed and the heterozygote manifests a third phenotype with properties of both alleles (blood type, red hairs and white hairs make red and white haired individual)

Answer 1

Codominance

Question 2

A single gene impacts two or more (seemingly unrelated) traits

Answer 2

Pleiotropy

Question 3

Variation due to this does not matter for evolution

Answer 3

Variation due only to environmental effects. Evolution is concerned with variation due to genes

Question 4

When there are no categories, anything size related (like height)

Answer 4

Continuous variation

Question 5

How do you perform a test cross?

Answer 5

Cross unknown genotype with homozygous recessive genotype

Question 6

During gamete formation, alleles segregate randomly so each gamete receives one or the other

Answer 6

Mendels law of segregation

Question 7

Alters larger sections of DNA, sections of chromosomes can get extra copies of missing parts

Answer 7

Unequal crossing over

Question 8

Example of pleiotropy

Answer 8

Holt Oram syndrome. Defective allele leads to abnormal heart and upper limbs

Question 9

What is Mendelian inheritance also known as?

Answer 9

Particulate inheritance

Question 10

Heterozygote results in a third unique phenotype, alleles are “blended” together (red hairs and white hairs make pink hairs)

Answer 10

Incomplete dominance

Question 11

Example of dominant not meaning common

Answer 11

Huntington’s chorea (Huntingtons disease, CAG repeats)

Question 12

How can mutations be predictable?

Answer 12

Bacterial resistance. Mutation occurs randomly but others die and the mutation gets passed on in the pop

Question 13

Provided a theory of heredity

Answer 13

Mendel

Question 14

What is simple dominance?

Answer 14

When there are two alleles, one dominant and one recessive

Question 15

How do mutation and recombination occur?

Answer 15

Randomly

Question 16

4 parts to Mendel’s law of segregation

Answer 16

1. Genes are passed on unchanged and alleles account for variation and inherited characters
2. Individuals inherit 1 allele from each parent
3. Two alleles of gene pair segregate randomly and equally into gametes, which combine randomly and equally in next gen
4. Traits may not show up in an individual but can still be passed on

Question 17

What was Mendel’s law of dominance?

Answer 17

There exists a form of a gene (allele) that will be the expressed phenotype over the other allele

Question 18

During gamete formation, segregating pairs fo alleles assort independently of other pairs (ability to form every combination, brown hair and brown eyes go to different gametes, etc.)

Answer 18

Independent assortment

Question 19

What does a higher h2 value mean for selection?

Answer 19

There is a stronger response to selection

Question 20

How did Mendelian genetics explain the problems of blending?

Answer 20

Blending caused rare variants to be blended out of the population by Mendelian genetics allowed rare variants to persist and become established in the population

Question 21

Example of recessive disease

Answer 21

Tay-Sachs Disease (neurological impairment due to accumulation of fatty acid derivatives in neurons)

Question 22

What is total variation (phenotypic variation) equal to?

Answer 22

Vp = Vg (genotypic variation) + Ve (environmental variation)

Question 23

Why did Darwin need Mendel?

Answer 23

Darwins theory of natural selection almost required heredity to be Mendelian

Question 24

Mutation altering single nucleotides

Answer 24

Point mutation

Question 25

What do heritabilites of 0 and 1 mean?

Answer 25

``` 1 = completely due to genes 2 = completely due to environment ```

Question 26

Is the act of ducks following their mom genetic or learned?

Answer 26

Both. Genetic = imprinting, Environmental = what to follow (mom)

Question 27

What is the equation for heritability?

Answer 27

``` h2 = Vg/Vp h2 = Vg/(Vg+Ve) ```

Question 28

Several genes may make products that contribute to phenotype; phenotype determined by interaction of multiple genes (eye color)

Answer 28

Polygenic traits

Question 29

What ration does a cross of first generation hybrids create?

Answer 29

3:1 in dominate

Question 30

Way of determining if a phenotype is environmentally or genetically determined by having common gardens for animals and having offspring raised by parents other than their own

Answer 30

Cross fostering

Question 31

One gene interferes with expression of another gene (bald gene interfering with widows peak gene)

Answer 31

Epistasis

Question 32

What were Mendel's three contributions?

Answer 32

Dominance, segregation, and independent assortment

Question 33

Way of determining if a phenotype is environmentally or genetically determined that determines whether phenotypes are inherited according to expectation of Mendelian laws

Answer 33

Controlled crosses

Question 34

Mechanism of heredity Darwin favored that said all cell lines contribute to gametes

Answer 34

Pangenesis

Question 35

How can we determine the genotype of an unknown individual displaying the dominant trait?

Answer 35

Test cross

Question 36

What is sickle cell anemia an example of?

Answer 36

Point mutation. T substituted for A

Question 37

Way of determining if a phenotype is environmentally or genetically determined that raise offspring under identical conditions and test effect of particular variables

Answer 37

Common garden experiments

Question 38

The proportion of variation that can be attributed to genotype

Answer 38

Heritability

Question 39

The ultimate source of all heritable variation

Answer 39

Mutation

Question 40

What happens when generation 1 dihybrids are crossed?

Answer 40

9:3:3:1 ratio

Question 41

What controls mutation rate?

Answer 41

Nothing, although mutations can be propagated or inherited randomly

Question 42

Theory of heredity that is supported that said certain cells (germ) are responsive for gamete production

Answer 42

Weismann's germplasm theory

Question 43

What kind of estimate is heritability?

Answer 43

Population wide, not individual

Question 44

What kind of heritability do things under high selection have?

Answer 44

Low heritability bc they have low genetic variation

Question 45

Multiple forms within a species

Answer 45

Polymorphism

Question 46

How do traits highly correlated with fitness influence heritability?

Answer 46

High fitness = lower heritability | Low fitness = higher heritability

Question 47

The interaction between these two is key

Answer 47

Genetics and environment

Question 48

When there are different categories; this is anything categorical (like color)

Answer 48

Discrete variation

Question 49

Shuffles existing variation into new combinations; creates new combos leading to greater levels of phenotypic variation

Answer 49

Recombination