Chapter five, test two

Question 1

what does syntenic mean

Answer 1

occurring on same chromosome

Question 2

what does / mean

Answer 2

separate genes found on the two chromosomes of a pair

Question 3

if the gametes from F1 mother assort independently what is the ratio

Answer 3

1:1:1:1

Question 4

if there is a gamete of 1:1:1:1 ratio from F1 female what are the two possible outcomes

Answer 4

parental type and recombinant type

1:1

Question 5

what is an explanation that the F1 female is more likely to pass on parental combinations of alleles

Answer 5

female inhertied wy+ together from p generation mom

inherited w+y together from p generation dad

Question 6

what shows linked genes

Answer 6

parental is greater than recombinant

Question 7

if the recombinant and parental is 32 and 67 what is the conclusion

Answer 7

still linked but not as tight

parental combination alleles travel together more often than not

Question 8

in mendels dihybrid, how does that work with linkage

Answer 8

the gamets dont happen in same ratio or fraction

no longer 9:3:3:1

Question 9

what is the point of testcross in dihybrid

Answer 9

decide if parent is doubly heterozygous

Question 10

who termed chiasmata

Answer 10

Frans janssens

Question 11

what helped researchers believe recombination occurred

Answer 11

physical markers that showed visual abnormalities being transferred

Question 12

what are genetic markers

Answer 12

alleles of genes that could serve as points of reference in determining whether particular progeny were the result of recombination

Question 13

who came up with the experiment that confirmed the exchange of genetic traits in dihybrids was associated with physical exchange between sister chromatids

Answer 13

Curt Stern

Question 14

physical exchange in allelic recombination

Answer 14

need two physical markers to show exchange

Question 15

what are synaptonemal complexes

Answer 15

help homologous chromosomes pair with each other

Question 16

what is needed to help keep sister chromatids together

Answer 16

cohesin

Question 17

what keeps the homologous chromosomes together at the metaphase plate and thus ensure proper chromosome segregation

Answer 17

cohesin

Question 18

who looked at linked genes

Answer 18

thomas hunt morgan

Question 19

who came up with recombination frequency

Answer 19

alfred sturtevant

Question 20

in a dihybrid with outcome of no cross over meiosis what will the gametes be

Answer 20

four parental gametes

Question 21

what about a single cross over in dihybrid, what are the gametes

Answer 21

2 parental

2 recombinant

Question 22

why is RF= 50% in a dihybrid for genes on nonhomologous chromosomes

Answer 22

nonhomologous chromosomes line up randomly to produce all parental or all recombinant in equal freq
meiosis that occur with one crossover bw one gene and centromere generate all four gamete types with equal freq

Question 23

double cross over 2 strand produces what recombination

Answer 23

no recombinants

Question 24

DCO 3 strand produces what recombination

Answer 24

50% recombinants

Question 25

DCO 4 strand produces what recombination

Answer 25

100% recombinants

Question 26

linked genes mean

Answer 26

must be syntenic and sufficiently close together on same chromosome

Question 27

unlinked genes mean

Answer 27

two genes on different chromosome or two genes on same chromosome but really far apart

Question 28

what are loci

Answer 28

maps that assign genes to specific locations on particular chromosomes

Question 29

what are some limitations of two point crosses

Answer 29

difficult to determine gene order if some gene pairs lie very close together actual distances dont always add up

Question 30

what could be the reason why in a 3 pt cross the distance from a to B and B to C does not equal A to C

Answer 30

double crossover could occur

Question 31

how to correct for double crossover in calculation total distance

Answer 31

count all recombinant numbers and count the dco twice | then divid by total progeny

Question 32

what is chromosomal interference

Answer 32

crossovers not occurring independently of each other

Question 33

what is the coefficient of coincidence

Answer 33

a ratio between the actual frequency of double crossovers observed in an experiment and number of double crossovers expected due to independent probabilities

Question 34

what if interference equals one

Answer 34

no double crossovers occur in experimental progeny because one exchange effectively prevents another

Question 35

what are recombination hotspots

Answer 35

small regions of DNA where the freq of recombination is much higher than average

Question 36

is there recombination occurring during meiosis in male flies

Answer 36

no

Question 37

what is a linkage group

Answer 37

genes chained together by linkage relationships

Question 38

any gene on chromosome is linked to another gene on the same chromosome then what

Answer 38

the number of linkage groups equals the number of pairs of homologous chromosomes in the species

Question 39

what is a chi square test

Answer 39

measures how well observed results conform to predicted ones account for size of experimental population

Question 40

what makes fungus a good species for gametes

Answer 40

they house all four haploid products of each meiosis in an ascus

Question 41

what is the fungus sac calles

Answer 41

ascus

Question 42

what are the haploid cells in ascus called

Answer 42

ascospores

Question 43

the phenotype of haploid fungi is a direct representation of their...

Answer 43

genotype | no complications of dominance

Question 44

meiosis in fungi produces

Answer 44

four haploid ascospores

Question 45

four haploid ascospores generate what in mitosis

Answer 45

8 haploid cells or 4 pairs

Question 46

what do the four pairs in the ascus represent

Answer 46

each pair represents the same genotype because they arose from mitosis

Question 47

can neurospora mate asexually

Answer 47

use during mitosis

Question 48

if neurospora come in opposite mating types what happens

Answer 48

zygote created and goes through mitotic cycles to reproduce

Question 49

what fungi produces unordered tetrads

Answer 49

yeast

Question 50

what fungi produces ordered tetrads

Answer 50

neurospora crassa

Question 51

what does tetrad mean in fungi

Answer 51

4 pairs of 8 haploids in ascus | four products of single meiosis

Question 52

tetrads can by characterized as

Answer 52

parental ditypes nonparental ditypes tetratypes

Question 53

parental ditype is

Answer 53

parental configuration iof alleles

Question 54

what is nonparental ditype

Answer 54

four recombinant spores , two of each type

Question 55

what is tetratype

Answer 55

four different kinds of spores | 2 recombinant and 2 parental

Question 56

how is RF determined in spores

Answer 56

recombinant #/ total number of spores

Question 57

second way to calculate RF

Answer 57

(NPD +1/2 (T))/ total tetrads

Question 58

how to get T tetrad progeny

Answer 58

crossover occurs between only one of the genes and the centromere

Question 59

no cross over produces what ditype

Answer 59

parental

Question 60

single crossover produces what ditype

Answer 60

tetratype

Question 61

double crossover 2 strand produces what ditype

Answer 61

parental

Question 62

DCO 3 strand produces what ditype

Answer 62

tetratype

Question 63

DCO 4 strand produces what ditype

Answer 63

nonparental

Question 64

what is first division segregation pattern (M1)

Answer 64

segregation of two alleles of a single gene at first meiotic division imaginary line drawn between 4th and 5th ascospores cleanly separate haploid showing the two alleles

Question 65

what is second division segregation pattern (M2)

Answer 65

crossover occurs in meiosis one cells with only one kind of allele show up at the end of second meiotic division not cleanly separated

Question 66

how to find mu with ascospores in M2 divisions

Answer 66

(1/2)M2/total tetrads x 100

Question 67

how do twin spots occur

Answer 67

during mitotic recombination

Question 68

what are twin spots

Answer 68

adjacent islands of tissue that differ both from each other and from the tissue surrounding them

Question 69

what is the function behind twin spots

Answer 69

when homozygous recessive phenotype cells are growing next to heterozygous cells showing dominant phenotype

Question 70

how does mitotic recombination occur

Answer 70

homologous chromosomes pair up and non sister chromatids crossover