Multiple-Locus Transmission Patterns Flashcards Preview

► Genetics > Multiple-Locus Transmission Patterns > Flashcards

Flashcards in Multiple-Locus Transmission Patterns Deck (22)
Loading flashcards...
1
Q

Mendel began his experiments with crosses involving…

A

one locus and two alleles

2
Q

Mendelian ratio for a cross of double heterozygotes with random segregation (not linked)

A

9:3:3:2

3
Q

Mendel’s second law

A

independent assortment

alleles at different loci and passed on independently

4
Q

when does Mendel’s second law breakdown?

A

when two genes are on the same chromosome and close together

alleles are not passed on independently, and are considered “linked”

5
Q

syntenic

A

two genes on the same chromosome

6
Q

does syntenic mean linked?

A

not always, they have to be close together and syntenic to be linked

7
Q

how to calculate offspring genotype and phenotype frequencies in non-linked loci?

A

multiply ratios

8
Q

when loci are linked, their association in transmission is…

A

stronger the closer together they are

9
Q

when is there more recombination?

A

when loci are farther apart

10
Q

when is there less recombination?

A

when loci are closer together

11
Q

can linkage be detected and recombination quantified in a two-locus testcross?

A

yes

12
Q

recombination frequency is typically calculated from…

A

two-locus testcross data

divide total recombinants by total offspring

13
Q

how can recombination frequencies can be expressed…

A

as a decimal fraction

percent

centiMorgans

14
Q

centiMorgan

A

one = 1% recombination

cM) not (cm

15
Q

another word for recombination events

A

crossovers

16
Q

are crossovers random?

A

yes, pretty much

17
Q

crude approximation …

A

one cM equals about one Mb (megabase) of DNA

18
Q

does the real crossover rate vary?

A

yes

19
Q

where is crossover rate lowest?

A

around centromeres and tips of the arms

20
Q

are recombination rates (frequencies) additive?

A

no

21
Q

crossover rates of less than 10%…

A

loci close together

related linearly to physical distance

22
Q

maximum possible recombination frequency between 2 syntenic loci is?

A

50%