Genetics 3 Flashcards Preview

MCBL > Genetics 3 > Flashcards

Flashcards in Genetics 3 Deck (31):
1

What is disease mapping dependent on?

genetic marker maps
meioses

2

How many markers are required for 10-20cM spacing ?

several hundred

3

Which generation is more informative for disease mapping?

second generations

4

What are genetic markers?

a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be observed

5

How can a disease map be analyzed with markers?

easily analyzed with PCR or hybridization

6

How can the Chromosomal location be determined with markers?

hybrid panels are genome search

7

What are first generation DNA markers and why aren't they sufficient?

They are restriction fragment length polymorphism(RFLPs)

they only give low information content (two alleles)

8

What are the second generation markers?

Minisatellites
microsatelites
single nucleotide polymorphism (SNPs)

9

What are minisatelites?

Numerous alleles (9-65 bp repeats) with high heterozygosity

10

how are minisatelites detected minisatelites?

detection by southern blotting (disadvantage
uneven distribution is a disadvantage

11

What are microsatelites?

large number of Di, tri, tetra nucleotide tandem repeats
they are the markers of choice

12

How are microsatelites detected?

PCR (multiplex flouresence)

13

What are single nucleotide polymorphism (SNPs)?

large number every 10Kb that are closely spaced
automation allows high throughput

14

What is the first step in gene mapping?

pedigree characterization

15

What is the second step in gene mapping?

typing with informative markers

16

What is the third step in gene mapping?

determine te recombination fraction

17

When are the marker and the disease not linked?

When there is a high recombination fraction
If the recombination is significantly less than 0.5 loci are linked

18

What will the recombination fraction never be higher than?

0.5
because there is a 50% chance that a gene will cross or not cross

19

If the recombinants cannot be calculated then what can be calculated?

the likelihood that thy are linked

20

What are can be assumed when calculating the likelihood of linked genes?

loci are linked recombination fraction = theta
not linked recombination fraction = 0.5

21

What are LOD scores?

logarithm of odds

22

How do determine the LOD?

calculate the odds and divide by 0.5
take the log of that number and that your LOD score

23

What has the maximum LOD?

most likely recombination fraction

24

What is the likelihood of odds a function of?

Theta

25

Why are LOD scores calculated?

for a range of theta

26

What are figuring when calculating LOD?

likelihood of linkage or no linkage

27

What does a LOD score has to say it is for sure linkage?

any number greater than or equal positive 3
any number less than positive 3 there some question or no linkage

28

How do you determine if the gene is linked to a particular marker?

Begin with marker framework
place disease gene in marker interval using algorithms
Curve of lod is obtained
highest peak is likely location

29

What is positional cloning?

Cloning of gene based on position on chromosome without knowing the function

30

What was the first gene identified by positional cloning?

Chronic granulomatous

31

how is positional cloning done?

Define candidate region
obtain clones of all DNA in region
identify all genes in that region
proritize them for mutation screening
test candidate for mutations in affected people

Decks in MCBL Class (70):