Bio 220 Exam 3

Define Epigenetics

Define Epigenetics

The differential expression of different genes with identical DNA based on methylation, acetylation, and exposure to different things

How do epigenetic mechanisms regulate transcription?

Transcription can be regulated via acetylation or methylation of the genome, as methyl tags inhibit transcription, and acetyl groups help promote it

What is genomic imprinting?

Regulation of a specific gene by silencing one copy of the gene (either from mother or father)

What are some possible outcomes of mutations in imprinted genes?

Overexpression of the gene, with two working copies, under-expression where neither copy is expressed can be fatal

How does the environment effect the epigenome?

Environmental exposure can change the way epigenetics impact our genes, like eating foods that can increase or decrease methylation, or exposure to harmful chemicals like BPA

What is alternative splicing?

When a gene is excised in different ways to create different protein products. A different combination of exons in the mRNA.

How is alternative splicing regulated?

Alternative splicing is regulated by various factors including splicing factors, RNA-binding proteins, and the phosphorylation state of the splicing machinery. Specific sequences within the pre-mRNA, known as splicing enhancers or silencers, play critical roles in determining which exons are included or excluded.

What factors confer tissue specific alternative splicing?

Similar to regulation of alternative splicing, including Cis-regulatory sequences, as well as RNA binding proteins.

What is miRNA?

Micro RNA, small segments about 22 nucleotides long, processed and used to aid regulation

How does miRNA aid regulation?

miRNA is complementary to RNA, and is processed and used by DICER, RISC, and a number of other proteins and units to bind to mRNA, and then excise or block segments.

What’s the difference between miRNAs and dsRNAs?

miRNAs are endogenous, coming from the organisms genome, processed by stem-loop precursors, and mainly regulate silencing of protein synthesis. dsRNAs can be exogenous, and often come from viral sources, they are cleaved from long complementary RNA sequences, and they trigger the RNA interference pathway

What are forward genetics?

Identification of genetic factors or genes that impact a given trait of interest, going from phenotype to genotype

What are reverse genetics?

Manipulation of genes to see the effect on physical characteristics, going from genotype to phenotype.