Multiple-Locus Transmission Patterns Flashcards Preview

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Flashcards in Multiple-Locus Transmission Patterns Deck (22)
1

Mendel began his experiments with crosses involving...

one locus and two alleles

2

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

9:3:3:2

3

Mendel's second law

independent assortment

alleles at different loci and passed on independently

4

when does Mendel's second law breakdown?

when two genes are on the same chromosome and close together

alleles are not passed on independently, and are considered "linked"

5

syntenic

two genes on the same chromosome

6

does syntenic mean linked?

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

7

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

multiply ratios

8

when loci are linked, their association in transmission is...

stronger the closer together they are

9

when is there more recombination?

when loci are farther apart

10

when is there less recombination?

when loci are closer together

11

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

yes

12

recombination frequency is typically calculated from...

two-locus testcross data

divide total recombinants by total offspring

13

how can recombination frequencies can be expressed...

as a decimal fraction

percent

centiMorgans

14

centiMorgan

one = 1% recombination

(cM) not (cm)

15

another word for recombination events

crossovers

16

are crossovers random?

yes, pretty much

17

crude approximation ...

one cM equals about one Mb (megabase) of DNA

18

does the real crossover rate vary?

yes

19

where is crossover rate lowest?

around centromeres and tips of the arms

20

are recombination rates (frequencies) additive?

no

21

crossover rates of less than 10%...

loci close together

related linearly to physical distance

22

maximum possible recombination frequency between 2 syntenic loci is?

50%