Chapter 8 - Epigenetics in Psych

Question 1

DNA methylation

Answer 1

Covalent modifications of mammalian DNA occurring via the methylation of cytosine, typically in the context of the CpG dinucleotide.

Question 2

DNA methyltransferases (DNMTs)

Answer 2

Enzymes that establish and maintain DNA methylation using methyl-group donor compounds or cofactors. The main mammalian DNMTs are DNMT1, which maintains methylation state across DNA replication, and DNMT3a and DNMT3b, which perform de novo methylation.

Question 3

Epigenetics

Answer 3

The study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence. Epigenetic marks include covalent DNA modifications and posttranslational histone modifications.

Question 4

Epigenome

Answer 4

The genome-wide distribution of epigenetic marks.

Question 5

Gene

Answer 5

A specific deoxyribonucleic acid (DNA) sequence that codes for a specific polypeptide or protein or an observable inherited trait.

Question 6

Genome-wide association study (GWAS)

Answer 6

A study that maps DNA polymorphisms in affected individuals and controls matched for age, sex, and ethnic background with the aim of identifying causal genetic variants.

Question 7

Genotype

Answer 7

The DNA content of a cell’s nucleus, whether a trait is externally observable or not.

Question 8

Histone acetyltransferases (HATs) and histone deacetylases (HDACs)

Answer 8

HATs are enzymes that transfer acetyl groups to specific positions on histone tails, promoting an “open” chromatin state and transcriptional activation. HDACs remove these acetyl groups, resulting in a “closed” chromatin state and transcriptional repression.

Question 9

Histone modifications

Answer 9

Posttranslational modifications of the N-terminal “tails” of histone proteins that serve as a major mode of epigenetic regulation. These modifications include acetylation, phosphorylation, methylation, sumoylation, ubiquitination, and ADP-ribosylation.

Question 10

Identical twins

Answer 10

Two individual organisms that originated from the same zygote and therefore are genetically identical or very similar. The epigenetic profiling of identical twins discordant for disease is a unique experimental design as it eliminates the DNA sequence-, age-, and sex-differences from consideration.

Question 11

Phenotype

Answer 11

The pattern of expression of the genotype or the magnitude or extent to which it is observably expressed—an observable characteristic or trait of an organism, such as its morphology, development, biochemical or physiological properties, or behavior.

Question 12

Epigenetic factors: Early Childhood Experiences

Answer 12

mother-infant bond and parental investment program the development ofindividual differences in stress responses in the brain: affects memory, attention, and emotion

Question 13

List important neural and developmental pathways that are regulated by epigenetic factors

Answer 13

Early childhood experiences, Child Nutrition, Learning and memory, Psychological disorders
Gene environment interactions

Question 14

Epigenetic factors: Childhood nutrition

Answer 14

nutrients can change or reverse DNA methylation and histone modifications- Nutrients can directly inhibit enzymes that catalyze DNA methylation/HM

Question 15

Epigenetic factors: Learning and Memory

Answer 15

Epigenetic mechanisms influence long-term changes in synaptic signalling, organization, and morphology- HM can influence long-term memory by altering chromatin accessibility and gene expression

Question 16

Epigenetic factors: Psychlogical Disorders

Answer 16

mental illnesses (depression)- Admin of antidepressants increased histone markers of increased expression: use HDACi inhibitors to combat depression