Genetics Exam 2

Front 1

Molecular Basis of Dominance and Recessiveness

Back 1

Expect gech gene copy would contribute in diff ways:
Dominant homozygous = each copy contributes equally
Heterozygote = one gene produces functional protein and one doesn't
Recessive homozygote - both genes produce non function protein

Front 2

Recessive Mutations

Back 2

Null mutations and Hypomorphs

Front 3

Null Mutations

Back 3

A mutation at a critical a.a. in enzyme's active site
- gives no functional protein product
- example: deletion of gene

Front 4

Hypomorph

Back 4

A mutation at a non critical a.a. in enzyme's active site
- causes a loss of some protein function (isn't efficiant)
- considered weak/ leaky form

Front 5

Dominant Mutations

Back 5

Haploinsufficient and Dominant Negative

Front 6

Molecular Basis of Dominance and Recessiveness

Back 6

Expect gech gene copy would contribute in diff ways:
Dominant homozygous = each copy contributes equally
Heterozygote = one gene produces functional protein and one doesn't
Recessive homozygote - both genes produce non function protein

Front 7

Recessive Mutations

Back 7

Null mutations and Hypomorphs

Front 8

Null Mutations

Back 8

A mutation at a critical a.a. in enzyme's active site
- gives no functional protein product
- example: deletion of gene

Front 9

Hypomorph

Back 9

A mutation at a non critical a.a. in enzyme's active site
- causes a loss of some protein function (isn't efficiant)
- considered weak/ leaky form

Front 10

Dominant Mutations

Back 10

Haploinsufficient and Dominant Negative

Front 11

Haploinsufficient

Back 11

A mutation not able to be functional with only one gene
- needs 2 functional genes
- not common, seen in developmental genes

Front 12

Dominant Negative

Back 12

A dominant mutation that is not haploinsufficient loci
It inhibits normal protein function
- seen in genes encoding proteins that dimerize

Front 13

Allelic Interactions

Back 13

Multiple alleles can act to influence one trait

Front 14

Allelic Series

Back 14

- A complete set of alleles
- All act to influence one trait
- Leads to varied phenotype patterns

Front 15

Lethal Mutations

Back 15

- Homozygous form causes lethality
- Causes a disturbance in Mendalian rations
- Example : yellow and agouti mice (homoz. dom for yellow = lethal)

Front 16

Pleiotropy

Back 16

- One gene affects many traits
- Example: coat color affecting viability

Front 17

Dominances (Types)

Back 17

Complete
Incomplete
Codominance

Front 18

Sickle Cell Anemia Examples

Back 18

- At normal O2 = COMPLETE
- At low O2 = INCOMPLETE/ CO
- W/ protection of malaria = COMPLETE
- Molecular phenotype = CO

Front 19

Epistasis

Back 19

- Expression of a phenotype is dependent on the allele(s) at another loci
- Ex. x -> y ->z need both func. enzymes to create z
- Have special ratios

Front 20

Epistasis Ratios

Back 20

9:3:4 = Recessive Epistasis (Labs)
9:7 = Duplicate recessive (albino snails)
12:3:1 = Dominant (squash color)

Front 21

Variable Penetrance

Back 21

Discribes the percent of individuals with a particular genotype that displaces phenotype
- ex. sex limited

Front 22

Full Penetrance

Back 22

When everyone has the same phenotype

Front 23

Expressivity

Back 23

Describes the "level" of the traits expression (varying degrees)
- common

Front 24

Variable Expressvity

Back 24

when the expressivity is varying at different levels
- ex spotting patterns in dogs
diff shades of a color

Front 25

Complementation Test

Back 25

Test used to determine if mutants of the same phenotype are caused by mutations of SAME or DIFF genes

Front 26

Complementation Test Steps

Back 26

1. get original mutant
2. create more mutants and find one with same phenotype
3. cross the new mutant with the original
4. see if F1 progeny complement or not

Front 27

NO COMPLEMENTATION OCCURS

Back 27

-F1: 2 mutations found
-Mutation is on same gene

Front 28

COMPLEMENTATION OCCURS

Back 28

- F1 is W.T.
- mutation is on different gene