population genetics

Question 1

What is species?

Answer 1

a discrete, reproductively defined system of populations with a common evolution

Question 2

what is a population?

Answer 2

A group of animals of one species which interbreed

Question 3

what is a gene pool

Answer 3

set of genes and or alleles in the netire population

Question 4

what is a breed?

Answer 4

a population distinguishable from another of the same species by frequencies of genes, chromosomal variation, or hereditary phenotypic characteristic

Question 5

what is population genetics

Answer 5

allele frequencies of a population of aniamals
in many species genes are fixed meaning all animals are homozygous for the same allele (all angus are polled)
A dominant and a recessive

Question 6

Hardy-Weinberg equilibrium?

Answer 6

p2+ 2pq + q2 = 1

Question 7

gene frequencies

Answer 7

autosomal recessive - q2
frequency of recessive allele the square root of q2

Question 8

frequency of an allele that is X linked recessive

Answer 8

= frequency in males - XY
or sqrt frequency in females XX

Question 9

gene frequencies remain stable if?

Answer 9

mating is random
no selection
no mutation
no migration
large population

Question 10

what happens in domestic animal breeding?

Answer 10

• humasn select which animals to breed
• in wild animals they choose their own mates
• hardy weinburg equilibrium - works for wild but has to be motified for domestic animals
  we have to calculate frequencies, if phenotypic selection is used

Question 11

what is snyders ratio?

Answer 11

based on phenotype - rarely know genome
used to determine proportion of recessive or dominant offspring per parental mating type

Question 12

What is genetic drift

Answer 12

small subpopulations become increasingly different over generations
Ex. rabbits change frequency changes in each generation
population size influences the allele frequency changes or drift

Question 13

what is the founder effect

Answer 13

founding a small population (herd)
gene frequency changes are due to chance

Question 14

what happens in breed introduction?

Answer 14

relatively small number of animals found thhe population
new population could be very differnt from parent population in terms of gene frequency

Question 15

what is a population bottleneck

Answer 15

severely reduced in numbers for 1 or more generations

Question 16

What is gene flow

Answer 16

exchange of new alleles between subpopulations
Panmictic populations : random mating in breeding population, exchange of breeding animals
genetic isolates: subpopulation breeds only within itself (closed herd)

Question 17

what is cline?

Answer 17

phenotypic gradients across a geographical region
gene flow is greatest between adjacent populations

Question 18

what is migration?

Answer 18

• migration of wild animals could be from their own movement
• in domestic animals, migration can include; putchase, trucking to a new barn or ranch - by owners
• migration of animals in the wild is typically some males and some females
  migration in domestication is buying males

Question 19

what effect of migration or gene flow depends on:

Answer 19

rate of immigration
difference in gene frequencies between the populations

Question 20

what are import-export regulations

Answer 20

can halt migration
australia demands karyotype on charolais
canada demands no foot and mouth

Question 21

what does migration do?

Answer 21

• assures a constant source of genetic variation
• retards random drift
• allows spread of a new negative or positive mutation

Question 22

what is the argument over genetic change

Answer 22

• domestic animal breeders want genetic change
  preservationists want no change

Question 23

what is artificial selection

Answer 23

choice of certain animals as breeding stock, based on certain traits
occasionally this operates counter to natural selection
large domestic turkeys that cant copulate