Chapter 5

Question 1

If p less than 0.05

Answer 1

statistically significant

confirm null hypothesis

null hyp is mendelian

Question 2

Syntenic genes

Answer 2

genes on the same alleles

can be reshuffled when crossing over occurs
= recombinant chromosomes

if genes close together, called linked genes

Question 3

Genetic linkage mapping

Answer 3

plots the position of genes and their relative distances from each other on chromosomes

looking at phenotypic ratios in offspring

Question 4

Independent assortment

Answer 4

mendelian

50% parental
50% recombinant

Question 5

Linked genes

Answer 5

no independent assortment

parental phenos more common than recombinant

physical relationship among genes located close to one-another

Question 6

Complete vs incomplete genetic linkage

Answer 6

complete = no crossover

incomplete = crossover in 40% of gametes

Question 7

The recombination frequency

Answer 7

r = number of recombinants / total number of progeny

further = recombine more
max value = 0.5

Question 8

Who confirmed genetic linkage

Answer 8

Morgan

used red and white eye flies

did a test cross

worked bc in drosophila recombination only occurs during oogenesis

Question 9

Test cross

Answer 9

between heterozygote and homozygous recessive parent

allows you to look at the alleles of the dihybrid (hetero) parent

Question 10

Morgan’s crossing-over hypothesis

Answer 10

crossing over creates parental and non-parental gametes after segregation

Question 11

First genetic linkage map

Answer 11

Sturtevant (morgan’s student) made the first chromosome map

discovered map units

Question 12

Map units

Answer 12

1% recombination
= 1 map unit (m.u.)
= 1cM

Question 13

Three point test cross

Answer 13

allows you to determine the location of three genes

cross a trihybrid individual with a homo recessive one

AaBbCc x aabbcc

Question 14

Which recombinations are most common

Answer 14

parental most common

double least common
(middle is the one that differs)

Question 15

Does data show evidence of genetic linkage

Answer 15

• if P value statistically significant, can accept genetic linkage hypothesis
• reject mendel independent assortment

Question 16

Single recombinations

Answer 16

(double + double + single + single)/total

look where only one gene is different than parental

abc
bc

look at where c is different

Question 17

Total gene distance

Answer 17

[(single + single + single + single) + 2(double)] / total

Question 18

Theoretical double crossover frequency

Answer 18

= (Psingle) x (Psingle)

then multiply by the number of individuals

Question 19

Is number of double crossovers usually higher or lower than expected

Answer 19

lower

due to interference

Question 20

More interference suggests

Answer 20

increased distance than map distance

Question 21

Coefficient of coincidence

Answer 21

C = (observed double recombinants)/(expected double recombinants)

Question 22

Interference (I)

Answer 22

Interference (I) = 1-C

Question 23

Negative interference

Answer 23

when there are more double recombinants than expected

I < 0

Question 24

Recombination frequency ______ actual distance between genes

Answer 24

underestimates

Question 25

Genetic analysis of humans

Answer 25

can't ethically do crosses human genome mapping done through mapping software

Question 26

Genetic markers

Answer 26

genetic sequences that are polymorphic and used for genetic analysis can be analysed from a DNA sample locate markers that are linked to alleles that determine phenotypic variation typically found in non-coding regions

Question 27

VNTRs

Answer 27

variable number tandem repeats shore 3-20 bp sequences of DNA can be amplified by PCR inheritance can be analyzed in a pedigree and show a codominant relationship

Question 28

RFLPs

Answer 28

restriction fragment length polymorphisms variable DNA sequences that are detected when extracting DNA and digesting it with restriction endonuclease enzymes - number and length varies at specific regions - VNTRs are usually RFLP markers

Question 29

SLPs

Answer 29

single nucleotide polymorphisms more commonly used single nucleotide at a specific position that is variable among populations some in coding, some in non-coding used by 23andme (detect 60 000 SNPs)

Question 30

Using genetic markers to detect disease

Answer 30

if close to gene of interest, usually inherited together and can be associated ex. SNPs A and B with disease gene D

Question 31

Haplotype

Answer 31

a series of linked SNPs on a specific chromosomal region