Quantitative Genetics - MCB 104

Question 1

Most traits in nature are ______

Answer 1

Quantitative

Question 2

What is quantitative genetics?

Answer 2

genetic analysis of complex traits (polygenic)

Question 3

How is a continuous trait inherited?

Answer 3

according to Mendel’s principles acting on alleles at two loci.

Question 4

relationship between loci and phenotypic classes

Answer 4

more loci = more phenotypic classes

Question 5

quantitative traits are described by _________

Answer 5

a frequency distribution.

Question 6

What are the types of quantitative traits available?

Answer 6

Question 7

Two methods to find a genotype variation causing a phenotype variation?

Answer 7

QTL and GWAS

Question 8

What is the difference between QTL and GWAS

Answer 8

Question 9

How could you start to figureout how a genome controls a phenotype?

Answer 9

Set up genetic crosses between genomes that control different phenotypes and ask whether genotypes at any genomic regions control phenotype!

Question 10

What is Quantitative trait loci (QTL)?

Answer 10

Chromosome regions containing a gene or genes that influence a quantitative trait

Question 11

How is QTL mapping conducted?

Answer 11

F2 intercross

Question 12

Which part of the genome can be genotyped?

Answer 12

Any region

Question 13

How does QTL mapping and molecular genotyping relate to one another?

Answer 13

chromosome regions can be molecularly genotyped so their segregation can later be followed in crosses and pedigrees using QTL strategies [Remember QTL mapping uses F2 cross]

1. First a region of a genome is molecularly genotyped.
2. for each genotyped region the F2 will fall into discrete categories [like AA, Aa, aa]
3. Genotyped markers that are linked are inherited together (more similar the inheritance pattern, the closer the linkage)

Question 14

___ can be measured in each F2 individual

Answer 14

any phenotype

Question 15

So how do you link genetic variation to phenotypes with QTL mapping?

Answer 15

1. genotype any genome region
2. for each genotyped region, F2s fall into discrete genotypic categories like AA, Aa, aA, aa
3. any phenotype can be measured in each F2 individual.
4. next see if the genotype categories differ in phenotype and if they do by how much?

Question 16

How do you know when a genotype correlates with a phenotype?

Answer 16

It is not possible sometimes to tell which is the clear genotype because many different genotypes overlap.

Question 17

How do you identify QTLs?

Answer 17

Question 18

How do geneticists map QTLs? use an example

Answer 18

Question 19

How can you tell which allele is the major determinant of a particular phenotype? Use IGF1 allele as an example.

Answer 19