Genome

Question 1

Define gene

Answer 1

A segment of DNA on a chromosome (nuclear and mitochondrial) that encodes a functional RNA

Question 2

Define genome

Answer 2

The entire complement of DNA in an organism

Question 3

What is the human genome made up of?

Answer 3

Only about 25% of genes have to do with proteins (1% exons, 24% introns), over 50% are transposons and replicated DNA

Question 4

What is the mitochondrial genome made up of?

Answer 4

37 genes, 22 tRNA, 2 rNA, 13 protein coding

Question 5

Noncoding RNAs

Answer 5

Have various functions, can be transcribed by either exons or introns

Question 6

Simple sequence repeats

Answer 6

Mini-satellites and micro-satellites

Question 7

Retrotransposons

Answer 7

Generated by the reverse transcription of RNAs into cDNAs and insertion into the genome (mostly from ERVs)

Question 8

Long interspersed nuclear elements

Answer 8

Replicated DNA with as many as 800,000 copies per genome, 3 families (line 1, line 2, and line 3)

Question 9

Short interspersed nuclear elements

Answer 9

Contain no protein encoding genes

Question 10

DNA transposons

Answer 10

Can be conservative or replicative, either changes location or increases in copy number (respectively)

Question 11

How is DNA packed into chromosomes?

Answer 11

DNA –> nucleosides –> 30nm fiber –> loops of fiber –> chromatin folding –> chromosome

Question 12

Define epigenome

Answer 12

Heritable changes in the genome and its expression that do not involve changes in the sequence of DNA

Question 13

How epigenomes are established

Answer 13

Modification of histone tails can alter gene transcription by tightening or loosening chromatin, or DNA methylation of cytosine to 5-methylcytosine attracts histone modification enzymes

Question 14

How epigenome is erased

Answer 14

During meiosis and fertilization by changing methylcytosine to hydroxymethylcytosine. Maybe not all is erased though, which is still a controversial idea at the moment

Question 15

Why is the human microbiome important to health and disease?

Answer 15

Our bodies contain a normal microbiome, which helps maintain our health in many ways, and disruption of this in any way can lead to disease

Question 16

What is circulating cell-free DNA?

Answer 16

DNA circulating in the bloodstream from various sources (like cell lysis, tumors, a fetus, transplanted organs, etc.)

Question 17

How can ccfDNA be used in a clinical sense?

Answer 17

As an early detection tool for cancers, fetal gene testing, and monitoring transplant rejection