exam 3

Question 1

in birds what are the male and female chromosomes

Answer 1

males- ZZ
females-ZW

Question 2

what is x-linkage

Answer 2

if a male receives a single x-linked recessive disorder allele from his mother will have the disorder

Question 3

what are lethal x-linked recessive disorders

Answer 3

observed only in males
2/3 inherited from mother
females can be heterozygous carriers

Question 4

what is sex limited inheritance

Answer 4

autosomal genes that are present in both sexes but are expressed only in one sex

Question 5

what type of inheritance causes the 2 sexes to show different phenotypes, despite having the same genotype

Answer 5

sex-limited inheritance

Question 6

if a hh female was Hen-feathered but a hh male was cock-feathered what inheritance?

Answer 6

sex-limited

Question 7

what is sex influenced inheritance

Answer 7

trait displayed by both sexes, but expression of genes depends on hormones

Question 8

what is penetrance

Answer 8

percentage of individuals having a particular phenotype that express the expected phenotype

Question 8

if a female is Bb and is not bald but a male with Bb is bald what kind of inheritance

Answer 8

sex influenced

Question 9

what is incomplete penetrance

Answer 9

a particular genotype does ot always produce expected phenotype

Question 10

in a pedigree that is autosomal dominant disorder is present and one of the sons of an affected mother does not have the disease what kind of penetrance would that be

Answer 10

incomplete, he has the allele but does not express even though passed on to children

Question 11

what is expressivity

Answer 11

the degree to which a trait is expressed

Question 12

if there is complete penetrance what kind of expressivity

Answer 12

narrow

Question 13

linkage is broken if crossing over occurs between the linked genes, what does this result in

Answer 13

recombinants

Question 14

independent assortment definition and ratio

Answer 14

no linkage exhibited- genes found on different chromosomes
1:1:1:1

Question 15

complete linkage definition and ratio

Answer 15

no crossover between 2 genes
1:1

Question 16

what is always the H0 when trying to identify whether the results are close enough to ratio

Answer 16

expected and observed are the same. If less than 0.05 you reject

Question 17

if crossover occurs in F1, four types of ___ are produced

Answer 17

gametes

Question 18

if genes are linked and are close together then what

Answer 18

very few crossover events- mostly parentals

Question 19

in the jack and jill problem where you try to find probability that their child will be type of blood and have the syndrome what should you do?

Answer 19

write out genotypes, find out if a parent crossed over in order to give baby affected genotype, if they did cross over- multiply recombinance divided by 2 times parental divided by 2

Question 20

when doing a 2 point cross what are the gametes that the female f1 could produce?

Answer 20

dont care about male- cross mom with herself to find babies

Question 21

if you are given mu and number of offspring how would you calculate which is parental and which is recombinant?

Answer 21

whatever mu is / 2
then to find parental- 100-mu/2

Question 22

when doing a 3 point cross the parentals should be …

Answer 22

biggest and reciprocal genotypes

Question 23

double cross over in a 3 point cross should be

Answer 23

least and reciprocals

Question 24

how to calculate map distance in a 3 point cross

Answer 24

adding single and double cross overs then dividing by total times 100

Question 25

what is asexual reproduction

Answer 25

offspring arise from a single organism and inherit genes of that parent only

Question 26

some animals can reproduce sexually and asexually true or false

Answer 26

true

Question 27

sexual reproduction

Answer 27

requires meiosis

Question 28

what is parthenogenesis

Answer 28

development of an embryo from and unfertilized egg

Question 29

what is haploidiploidy

Answer 29

males develop from unfertilized eggs that are haploid females develop from fertilized eggs and are diploid

Question 30

how does temperature affect modes of sex determination

Answer 30

affects enzyme activity and inhibitors which control production of sex hormones

Question 31

what are hermaphrodites or monoecious

Answer 31

have both female and male reproductive organs

Question 32

what is intersex

Answer 32

sex characteristics that do not fir typical binary notions of male or female bodies

Question 33

what is aneuploidy in humans

Answer 33

abnormal number of chromosomes in a cell

Question 34

examples of aneuploidy

Answer 34

turner syndrome- 45, X down syndrome- 47, XY +21

Question 35

how does aneuploidy occur

Answer 35

due to failure of chromosomes to separate during meiosis or mitosis(nondisjunction)

Question 36

difference between nondisjunction occurring in meiosis one or 2

Answer 36

1- all aneuploids 2- 2 normal babies

Question 37

what is klinefelter syndrome

Answer 37

47, XXY intersex condition- partial female partial male

Question 38

what is turners syndrome

Answer 38

45, X- missing and X thought to end in miscarriages or stillbirths phenotypically female mosaics -nondisjunction early in meiosis

Question 39

triplo X syndrome

Answer 39

47, XXX taller than average but phenotypically normal

Question 40

jacobs syndrome

Answer 40

XYY only consistently shared characteristic is that men are over 6 feet tall

Question 41

embryonic structures are considered

Answer 41

bipotential- 2 gonads that can go either way

Question 42

one pair of gonads consist of

Answer 42

cortex and medulla

Question 43

what does cortex develop into and what does the medulla develop into

Answer 43

cortex- ovary medulla-testes

Question 44

what are the 2 pairs of undifferentiated accessory ducts

Answer 44

wolffian ducts- become male internal structures mullerian ducts- female internal structures

Question 45

is a Y-linked trait dominant or recessive

Answer 45

doesnt apply no counterpart

Question 46

what does the PAR region of the Y chromosome share

Answer 46

homologous genes and synapses and recombines with X during meiosis

Question 47

what does the euchromatic region of a Y chromosome contain

Answer 47

SRY gene

Question 48

what does the heterochromatic region of Y chromosome do

Answer 48

nothing- lacks genes

Question 49

what is the lyon hypothesis

Answer 49

one of 2 copies of the X chromosome present in females is inactivated (Barr body)

Question 50

what are the different ways to turn on the SOX9

Answer 50

in mammals- SRY gene anything else- Dmrt1