In Class Notes taken for Chapter 2-4

Question 1

what is epigentics

Answer 1

study of modifications of the human phenotype or gene expression that occur apart from DNA mutations

Question 2

Various epigenetic mechanisms that cause genes to be expressed or silenced
(what are the three)

Answer 2

DNA methylation – a methyl group attaches to a cytosine
Histone modifications
RNA-based mechanisms

Question 3

DNA methylation
results from what?
what can it lead to?
DNA is less likely too..?

Answer 3

Results from attachment of methyl group to cytosine
Renders genes silent
Prominent role in health and disease
Aberrant methylation can lead to misregulation of tumor-suppressor genes and oncogenes
When a gene becomes heavily methylated, the DNA is less likely to be transcribed into mRNA

Question 4

Histone Modification
what are histones?
what does it include, ends what?
what is chromatin?

Answer 4

Histones
Proteins that facilitate compaction of DNA into the nucleus of a cell
Histone modifications include histone acetylation and deacetylation to the end of a histone protein

Chromatin
DNA in association with histones
Critical role in determining development of cells

Question 5

RNA-Based Mechanisms

-describe noncoding RNAs (what’s it’s role) 2 points

Answer 5

Role in RNA splicing and DNA replication

“Sop up” complementary RNAs

Question 6

RNA-Based Mechanisms
-describe Micro RNA/s (miRNAs)
what does it modulate? (4 points)

Answer 6

Modulate the stability and translational efficiency of existing messenger RNAs

Specific and general

Oncomirs

miRNAs that stimulate cancer development

Question 7

Prader-Willi and Angelman syndromes

-know if its inherited from father/mother

Answer 7

Deletion of 4 million base pairs of long arm of chromosome 15
Manifestations of Prader-Willi syndrome if inherited from father
Short stature, hypotonia, small hands and feet, obesity, mentally challenged
Manifestations of Angelman syndrome if inherited from mother
Severely mentally challenged, seizures, ataxic gait
Indistinguishable at DNA sequence level

Question 8

Genetic conflict hypothesis

-know imprinting on mother/father

Answer 8

Imprinting of maternally inherited genes tends to reduce offspring size
Imprinting of paternally inherited genes tends to increase offspring size