Genetics 3

Question 1

Heritability

Answer 1

-the proportion of the phenotypic variation that can be passed from parent to offspring
-can be used to predict the rate of genetic progress
-values in the range 0-1

Question 2

Low Heritablilty:

Answer 2

0-0.2
reproductive traits

Question 3

Moderate heritability

Answer 3

0.3-0.4
growth rates

Question 4

High Heritability

Answer 4

0.5-0.6
Carcass Traits

Question 5

Selectional difference

Answer 5

Selected animal measurement-group average=selection differential

Question 6

Generational Interval

Answer 6

-Average period of time between the birth of one and the birth of the next generation

Gen interval= (average age of breeding females+average age of breeding males) /2

Question 7

Generational Interval per species

Answer 7

Beef: ⅚ years
Dairy:¾ years

Question 8

Genetic progress dependent on

Answer 8

-heritability
-selectional differential
-generation interval-animals with shorter generation intervals will exhibit more rapid genetic progress

Question 9

Population genetics: Hardy-Weinberg equilibrium

Answer 9

-gene and genotype frequencies remain constant in a population
-does not occur in domesticated animal populations

Question 10

Requirements’ for Hardy-Weinberg equilibrium

Answer 10

-large population
-random mating
-no migration
-no mutations
-no selection

Question 11

Genetic Drift

Answer 11

-each generation will have a new frequency of alleles and genotype frequencies
-2 special cases

Question 12

Bottleneck

Answer 12

small population size for at least 1 generation created less genetic variation

Question 13

Founder Effect

Answer 13

when a new colony is created from only a few members of a previous colony less genetic variation exists

Question 14

Mutations

Answer 14

-mutation is simply a change in the DNA that can affect the expression of a gene
-form abnormal proteins
-reduce synthesis of proteins
-change the rate of protein synthesis

Question 15

Mutations are permanent changes due to

Answer 15

-DNA breakage
-DNA loss
-DNA rearrangement

Question 16

Mutations in Germline cells:

Answer 16

These cells create gametes
can be inherited

Question 17

Mutations in Somatic cells

Answer 17

not inherited
usually give rise to cancers and some congenital conditions

Question 18

Causes of mutations

Answer 18

-environment
-excessive UV light, radiation
-errors during cell division

Question 19

Cause of somatic cell mutations during cell division

Answer 19

mitosis

Question 20

cause of germline cell mutations during cell divison

Answer 20

mesisos

Question 21

Can mutations be fixed?

Answer 21

depends
Cells contain dna repair proteins to proofread and fix mistakes in the dna

Question 22

Point Mutation

Answer 22

-single nucleotide base is substituted by a different base

Question 23

types of point mutations

Answer 23

silent
missense
nonsense

Question 24

Silent point mutation

Answer 24

no effect on protien sequence

Question 25

Missense point mutation

Answer 25

results in an amino acid subsitiuion

Question 26

Nonsense point mutation

Answer 26

subsitiutes a stop codon for an amnio acid

Question 27

Frameshift mutation

Answer 27

–one or two base pairs may be inserted to or deleted from a dna sequence -alters the reading frame for codons-throws off mRNA -changes every amino acid -more severe than point mutation