Imprinting, Epigenetics, Cytogenics

Question 0

Imprinting takes place during _________

Answer 0

Gametogenesis, before fertilization

Question 1

Imprinting makes offspring functionally ______

Answer 1

Hemizygous, since 1 gene is never going to be expressed despite its presence

Question 2

What are two ways that demethylation occurs in wholescale erasure?

Answer 2

1. Inhibition of maintainance methyltransferase, DMNT1
2. Inactivation of chromatin remodeling protein

(To get rid of imprinting)

Question 3

Do imprinting centers contain coding or no coding DNA sequences?

Answer 3

Non coding DNA sequences

Question 4

Imprinting

Answer 4

Allele specific methylation of CpG dinucleotides to inactivate/silence genes

Question 5

How can hyper methylation silence genes?

Answer 5

1. Repelling txn factors

2. Actively recruit factors that repress txn

Question 6

How does uniparental disomy result?

Answer 6

Trisomy can conceptus loses one of its extra ch due to mitotic ND in early gestation.

This rescues developing pregnancy from spontaneous abortion, but remaining homolog may be derived from same parent.

Question 7

3 characteristics of imprinted genes

Answer 7

1. Tend to be clustered together on genome
2. Clusters contain both paternally and maternally imprinted genes
3. Imprinted gene encodes both proteins and non coding RNAs

Question 8

4 characteristics of epigenetics

Answer 8

1. Different gene expression pattern/phenotype
2. Inheritance through cell division (even through generations)
3. Like a “on off” switch
4. Eraseable (interconvertible)

Question 9

What principle explains the differentiation pattern of cells?

Answer 9

Waddington’s epigenetic landscape

Question 10

microRNA as an epigenetic ______

Answer 10

regulator (regulatory RNA)

function in silencing by affecting cytosolic proteins

Question 11

Name a specific type of gene that, when abberantly methylated w 5MeC, can lead to cancer.

Answer 11

Silencing Tumor suppressor genes (TSG) with 5MeC.

Remember, TSG are the breaks on cancer
TSG can also be silenced by age/environment/mutation

Question 12

Two most common types of leukemia translocation

Answer 12

1. t(9:22) for chronic lymphocytic leukemia (ie CML)

2. t(15:17) for acute myeloid leukemia (AML)

Question 13

3 common types of FISH probes used to detect leukemias

Answer 13

1. centromere
2. Locus specific (p53)
3. Fusion or DNA1 Fusion

Question 14

centromere FISH probes detect what

Answer 14

Enumeration (repetitive DNA seq) leukemias

Question 15

Locus specific FISH probes detect what

Answer 15

Deletion leukemias

Question 16

Fusion/DNA1 fusion FISH probes detect what

Answer 16

Translocation leukemias

Question 17

Chromosomal Microarray Analysis (CMA)

Answer 17

Whole genome can be investigated simultaneously - like performing thousands of FISH tests

Detects genomic deletions and duplications (amplifications) only

(does not detect translocations, mosaicism)