Genetic Linkage And Gene Mapping

Question 1

How is linkage broken

Answer 1

Crossing over

Question 2

Does linkage follow mendels law

Answer 2

No

Question 3

Frequency of recombination formula

Answer 3

Frequency of recombination= no of recombinant ×100/total no of progeny

1% recombination - 1 cell out of 50

Question 4

Cis and trans configuration of homologous chromosome

Answer 4

Cis/coupling- linked genes on each chr are of same type- AB or ab
Trans/repulsion -linked genes on each chr are of different types Ab or aB

Question 5

Difference between recombination frequency of cis and trans configuration of homologous chr

Answer 5

Same

Question 6

Genetic mapping and what does it tell and unit

Answer 6

It shows relative location of gene on chr. It is based on linkage
Made by using frequency of crossing over

It tells
Gene order and gene distance

Unit cM(centi morgan)
cM/map unit=frequency
3.5%=3.5cM

Question 7

1cM= how many base pairs

Answer 7

10^6

Question 8

Hot and cold spot on crossing over

Answer 8

Hot- more no of recombinant hotspot

Question 9

How to identify if gene are linked or unlinked

Answer 9

If unlinked all phenotype class should be in equal no

Question 10

Gene distance formula

Answer 10

No of single cross over+ double cross over×100/total progeny

Question 11

Purpose of two point cross and three point cross

Answer 11

Two point cross- tells gene distance
Three point cross- tells gene order