Chapter 4: Genes and Their Evolution: Population Genetics

Question 1

Heritability

Answer 1

Proportion of phenotype variation in a population that is due to genetic variation within individuals in the population, rather than variation in the environment conditions experienced by those individuals. Heritability varies from population to population.

Question 2

Heritability Equation

Answer 2

H^2 = genetic variation / (genetic variation + environmental variation)

Question 3

Fitness

Answer 3

average number of offspring from particular genotype, which causes evolutionary genetic change, based on number of children you have.

Question 4

Deme

Answer 4

a local population that interbreeds

Question 5

Gene Pool

Answer 5

all the genetic information in a breeding population

Question 6

Reproductive Isolation

Answer 6

any mechanism that prevents two populations from interbreeding, could be caused by geographical distance, life habits, and chromosomal difference

Question 7

Species

Answer 7

groups/populations/lineages of reproductively isolated organisms.

Question 8

Microevolution

Answer 8

allele changes from generation to generation within a species/population

Question 9

Macroevolution

Answer 9

allele/other changes involving speciation (new species development) or larger scale evolution

Question 10

Equilibrium

Answer 10

system is stable, balanced, unchanging-evolution is a departure from equilibrium

Question 11

Lactase persistence alleles

Answer 11

PP-lactase persistent
PR-heterozygous for lactase non-persistance-intermediate enzyme output
RR-homozygous for non-persistance

Question 12

Hardy-Weinberg Equilibrium Formula

Answer 12

p^2+2pq+q^2=1

Question 13

Hardy-Weinberg Equilibrium “If” Assumptions

Answer 13

• arbitrarily large population (approaching infinity)
• random mating
• all members produce same number of offspring

“Then” genotype frequencies of 1 gene remain the same after 1 generation.

Never happens but species approximate this.

Question 14

Hardy-Weinberg Equilibrium “If Not” Assumptions

Answer 14

I. Mutation
II. Natural Selection
III. Genetic Drift
IV. Gene flow are taking place

Question 15

Gene Frequencies

Answer 15

look at % of offspring to estimate % of p and q

Question 16

Point Mutations

Answer 16

Mutations in the coding sequence

Question 17

Synonymous Point Mutation

Answer 17

does not change amino acid code

Question 18

Non-Synonymous Point Mutation

Answer 18

amino acids do change

Question 19

Frameshift Mutations

Answer 19

insert or delete nucleotide, the three sets of codons are shifted up one or down one

Question 20

Transposable Mutations

Answer 20

foreign invaders DNA, come from viruses, they insert into codons and throw off reading frame

Question 21

Spontaneous Mutations

Answer 21

1 new mutation per 1000 replications

Question 22

Induced Mutations

Answer 22

radiation and chemical mutagens, breaks Hydrogen bonds in DNA molecules, enzymes fix DNA usually incorrectly

Question 23

Silent Mutations

Answer 23

a synonymous mutation, no change in amino acids

Question 24

Missense Mutations

Answer 24

a non-synonymous mutation, change into another amino acid

can be caused by frameshift

Question 25

Nonsense Mutations

Answer 25

change occurs where there is a dead stop, truncates the polypeptide coding Fram, can't be completed can be caused by frameshift

Question 26

Klinefelter's Syndrome

Answer 26

An individual has XXY the genotype of male and female t the same time

Question 27

Down syndrome

Answer 27

Trisomy of the 21st chromosome

Question 28

Pleiotropic Mutation

Answer 28

when genes change and affect many traits: white cat, blue eyes, deafness, timidity

Question 29

Homeotic Mutation

Answer 29

Appearance of a body part in another place than it's supposed to be: Fruit fly has eye appearance in wrong morphological location

Question 30

Directional Selection

Answer 30

Favors one extreme form of a trait | ex. more children produced by people with extreme trait, selection moves that direction

Question 31

Stabilizing Selection

Answer 31

Favors the average version of a trait | ex. humans with middle range birth weight have high chance of surviving than those with low and high birth weight

Question 32

Disruptive Selection

Answer 32

pattern of variation is discontinuous | ex. very tall, very short people are favored

Question 33

Sickle Cell and Malaria Genotype Distribution

Answer 33

AA- Homozygous for normal red blood cells susceptible to malaria AS- Heterozygous for red blood cells immune to malaria SS- Homozygous for sickle cell anemia

Question 34

Balanced Polymorphism

Answer 34

Selection maintains two or more phenotypes for a specific gene in a population

Question 35

Anthropogenic

Answer 35

effects caused by humans

Question 36

Thalassemia

Answer 36

short lived red blood cells

Question 37

G6PD

Answer 37

Glucose 6-Phosphate Dehydrogenase- lack of enzyme leads to rupturing red blood cells, or hemolytic anemia

Question 38

Effective Population Size

Answer 38

Ne- number of organisms in a population contributing offspring to next generation

Question 39

Evolution

Answer 39

Change in allele frequencies in populations over generations

Question 40

Exogamous

Answer 40

Mating without or outside the group

Question 41

Endogamous

Answer 41

Mating within a group

Question 42

Dunkers

Answer 42

Religious group that discouraged outside marriage, very endogamous

Question 43

Genetic Bottlenecks

Answer 43

A small portion of the population survives some catastrophe (survivors are not genetically representative of the entire population

Question 44

Founder effect

Answer 44

a small portion of the population finds a new colony with colonist who are not genetically representative of the entire original population (accumulation of small changes in small, isolated populations)

Question 45

Gene Flow

Answer 45

Organisms migrate into new areas, bringing their alleles with them, bringing changes

Question 46

Admixture

Answer 46

exchange of genetic material between 2 or more populations

Question 47

Exogamous Gene Flow

Answer 47

more gene flow, more genetic variation

Question 48

Endogamous Gene Flow

Answer 48

less gene flow, less genetic variation

Question 49

Patrilocal

Answer 49

males remain in birthplace; females migrate

Question 50

Matrilocal

Answer 50

females remain in birthplace; males migrate

Question 51

Summary: Mutation-, Natural selection-, Genetic Drift-, Gene Flow-,

Answer 51

Mutation: rise of new alleles Natural Selection: selection favors individuals with certain phenotype Genetic Drift: Small sampling into new population, random fluctuation Gene Flow: organisms with genes migrate