Linkage Mapping

Question 1

Two type of genetic mapping:

Answer 1

Linkage mapping (mono genetic diseases), association mapping (polygenic diseases)

Question 2

What is recombination?

Answer 2

crossing over that generates genetic variation during meiosis

Question 3

Linkage relationship with distance:

Answer 3

genes far apart crossover mroe frequent genes close together crossovers are less likely to occur between them

Question 4

What is RF (recombination frequency)?

Answer 4

the distance between 2 loci that can be inferred by estimating how frequently recombinations occurs in families

Question 5

Recombination frequency values meaning:

Answer 5

A value of 0 means 2 genes are so close that they never recombine, a value of 0.5 implies that the genes are unlinked

Question 6

What are genetic markers?

Answer 6

A genetic marker is a DNA sequence with a known location on a chromosome (RFLps, VNTRs, micro satellites, SNP)

Question 7

What is linkage phase?

Answer 7

arrangement of alleles on each chromosome

Question 8

What makes a marker useful

Answer 8

To be useful in gene mapping linked markers should be numerous and highly polymorphic

Question 9

LOD score is

Answer 9

Log10 [prob assuming linkage/ assuming NO linkage]

Question 10

LOD score meanings:

Answer 10

LOD score . 3 are taken as evidence of linkage corresponds to 1000:1 odds

Question 11

Issues with LOD scores:

Answer 11

unclear mode of inheritance, locus of heterogeneity, difficulty finding extended pedigrees, penetrate of disease may be incomplete