Lecture 31 - Epigenetics II

Question 1

What is genomic imprinting?

L31 S21

Answer 1

Expression of an allele is based on which parent it was inherited from

Question 2

What is uniparental disomy?

L31 S23

Answer 2

When a genotype contains two a chromosome but instead of being one from each parent they are both from the same parent

Question 3

How do Prader-Willi syndrome and Angelman syndrome relate to genomic imprinting?

L31 S23

Answer 3

Prader-Willi syndrome:
-responsible genes of chromosome 15 are only active on the paternal chromosome

Angelman syndrome:
-responsible genes of chromosome 15 are only active on the maternal chromosome

Question 4

What is the hypothesis for why a majority of the imprinted genes are related to embryological development?

L31 S24

Answer 4

It is not advantageous for females to invest too much energy into a single baby as it will limit how many children she can have.

As males do not invest as much energy into raising children, other than initial fertilization, they want to produce as many strong offspring as possible without regard to how much energy it costs.

Question 5

What does bisulphite treatment of DNA show?

L31 S34

Answer 5

Converts cytosines to uracil but leaves methylcytosines intact.

Shows methylated and unmethylated locations when comparing treated and untreated sequences.

Question 6

What is ChIP-Seq?

L31 S35

Answer 6

Precipitation of methylated DNA fragments with antibodies specific for methylated DNA.

Precipitated sequences are then sequenced.