Genetics Exam 2

Question 1

How do Sex Chromosomes pair up during meiosis?

Answer 1

Pseudo autosomal regions

Question 2

H0 (null hypothesis)

Answer 2

deviations between the expected and observed ratios/numbers are due to random chance/sampling error

Question 3

Ha

Answer 3

Random chance does not explain the differences between the observed and expected observations for a sex linked trait
1. therefore, the trait is due to something else

Question 4

dimer

Answer 4

two proteins

Question 5

homodimer

Answer 5

two of the same dimer

Question 6

heterodimer

Answer 6

two different dimers

Question 7

Mammals and flies

Answer 7

females are the homogametic sex (XX) and males are the heterogametic sex (XY)

Question 8

Butterflies and Birds

Answer 8

Males are the homogametic sex (ZZ) and females are the heterogametic sex (ZW)

Question 9

necessary

Answer 9

it is needed to work

Question 10

sufficient

Answer 10

it can work by itself

Question 11

turner syndrome

Answer 11

X0

Question 12

Kleinfelter syndrome

Answer 12

XXY

Question 13

Androgen insensitivity syndrome

Answer 13

low response to hormones (testosterone), common cause for XY females

Question 14

Congenital adrenal hyperplasia

Answer 14

high production of hormones (testosterone), XX individuals can be: typical male, combines female and male characteristics, typical female

Question 15

Polyploid

Answer 15

when there are more than 2 complete sets of chromosomes (not viable in humans)

Question 16

aneuploid

Answer 16

an abnormal number of one or more chromosomes, most are lethal

Question 17

SRY

Answer 17

activates male development pathways: SRY produces transcription factor TDF which activates testes-promoting genes and represses ovary-promoting genes
- causes undifferentiated gonad to form into testes

Question 18

Leydig cells

Answer 18

produce testosterone

Question 19

Sertoli cells

Answer 19

produce anti-mullerian hormone

Question 20

Wolffian duct

Answer 20

develops into vas deferens

Question 21

mullerian duct

Answer 21

becomes oviduct

Question 22

Population genetics

Answer 22

understand how and why allele frequencies change over time within and between populations

Question 23

polymorphisms

Answer 23

individuals of a population often display different phenotypes, or express different alleles of a particular gene

Question 24

population variation

Answer 24

the distribution of phenotypes among individuals. Influenced by genetic structure of population and the environment

Question 25

natural selection

Answer 25

can only act on heritable traits

Question 26

acquired traits

Answer 26

traits that are usually not heritable (ex: strength, languages)

Question 27

heritability

Answer 27

the fraction of phenotype variation that can be attributed to genetic differences among individuals in a population

Question 28

genetic drift

Answer 28

allele frequencies change sue to chance (ex: chance mating) - natural disaster= decrease/change allele frequencies

Question 29

gene flow

Answer 29

2 distinct populations of aa species that are not breeding that start breeding and change allele frequencies

Question 30

bottleneck effect

Answer 30

whoever makes it through will establish the new population

Question 31

gene pool

Answer 31

the set of all genes (alleles) in a population

Question 32

HWE assumptions

Answer 32

-no selection (each allele has equal fitness) - random mating - no migration in or out of the population - no mutation (no new alleles) - large population size - organisms are diploid

Question 33

evolution

Answer 33

changes in allele frequency of a population over (generational) time

Question 34

In a population, allele frequencies are a reflection of _______

Answer 34

genetic diversity

Question 35

If the assumptions of HWE are met, allele frequencies _________

Answer 35

don't change over time

Question 36

departures from the 1:1:1:1 ratio indicates... or 9:3:3:1

Answer 36

that the two genes are on the same chromosome (linked) for AaBb x aabb test cross or AaBb x AaBb

Question 37

there are ______ parental types than recombinant types

Answer 37

more

Question 38

nonrecombinant

Answer 38

has genotype of parent-> no crossovers occurred

Question 39

recombinant

Answer 39

different than the parent

Question 40

complete linkage

Answer 40

all nonrecombinant; no crossing over

Question 41

genes of different chromosomes yield ____% recombination frequency

Answer 41

50%, because of independent assortment **genes that lie far apart on the same chromosome also show 50%

Question 42

How do you show definitely that two genes are on the same chromosome?

Answer 42

show definite linkage with other genes that are between them

Question 43

genetic linkage

Answer 43

a physical relationship between genes located near one another on a chromosome

Question 44

syntenic genes

Answer 44

physically located on the same chromosome

Question 45

recombination

Answer 45

occurs between linked genes in fewer then 50% of meiotic divisions--> more than 50% of gametes will contain parental combinations of alleles

Question 46

incomplete linkage

Answer 46

crossing over leads to recombinant gametes

Question 47

What did human migration do?

Answer 47

carried subsets of genetic diversity to new locations. Each population established different allele frequencies - genetic testing companies use these population -level allele frequencies to guess your genetic ancestry

Question 48

ancestry reports

Answer 48

determine percentage of your DNA that originated from different populations

Question 49

Companies save money by testing ___

Answer 49

SNPs

Question 50

haplotype

Answer 50

a set of SNPs found on the same chromosome

Question 51

Since we are diploid, how many haplotypes do we have for a stretch of DNA?

Answer 51

2

Question 52

Genetic Admixture

Answer 52

occurs when previously diverged or isolated genetic linkages mix

Question 53

By how much does ancestral DNA decrease with each generation?

Answer 53

it is approximately halved