Week 3 - Genetics and Evolution Flashcards
What is DNA methylation?
Covalent modifications of mammalian DNA occurring via the methylation of cytosine, typically in the context of CpG dinucleotide.
What is DNA methyltransferases (DNMTs)?
Enzymes that establish and maintain DNA methylation using methyl-group donor compounds or cofactors.
What is the main mammalian DNA methyltransferase?
DNMT1, which maintains methylation state across DNA replication, and DNMT3a and DNMT3b, which perform de novo methylation.
What is epigenetics?
The study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence. They included covalent DNA modifications and posttranslational histone modifications.
What is an epigenome?
The genome-wide distribution of epigenetic marks.
What is a gene?
A specific deoxyribonucleic acid (DNA) sequence that codes for a specific polypeptide or protein or an observable inherited trait.
What is a genome-wide association study?
A study that maps DNA polymorphisms in affected individuals and controls matched for age, sex, and ethic background with the aim of identifying causal genetic variants.
What is a genotype?
The DNA content of a cell’s nucleus, whether a trait is externally observable or not.
What are histone acetyltransferases (HATs)?
Enzymes that transfer acetyl groups to specific positions on histone tails, promoting an “open” chromatin state and transcriptional repression.
What are histone deacetylases (HDACs)?
Enzymes that remove acetyl groups, resulting in a “closed” chromatin state and transcriptional repression.
What are histone modifications?
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.
What are identical twins?
Two individual organisms that originate from the same zygote and therefore are genetically identical or very similar.
What is a phenotype?
The pattern of expression of the genotype or the magnitude or extent to which it is observably expressed - an observational characteristic or train of an organism.
What are adaptations?
Evolved solutions to problems that historically contributed to reproductive success.
What is the error management theory (EMT)?
A theory of selection under conditions of uncertainty in which recurrent cost asymmetries of judgment or inference favor the evolution of adaptive cognitive biases that function to minimize the more costly errors.
