Chapter 20

Front 1

Human Genome Project

Back 1

The multinational research project that sequenced the human genome.

Front 2

Genomics

Back 2

The field of study concerned with sequencing, interpreting, and comparing whole genomes from different organisms.

Front 3

Functional Genomics

Back 3

The study of how a genome works, that is, when and where specific genes are expressed and how their products interact to produce a functional organism.

Front 4

Shotgun Sequencing

Back 4

A method of sequencing genomes that is based on breaking the genome into small pieces, sequencing each piece separately, and then figuring out how the pieces are connected.

Front 5

Steps in shotgun sequencing a genome

Back 5

1. Cut DNA into fragments using sonication.

2. Clone using BACs.

3. Purify copies and cut into small fragments.

4. Clone using plasmids.

5. Sequence each fragment by finding overlap.

6. Assemble all the small fragments into the larger fragments.

7. Assemble larger fragments into sequence.

Front 6

Bacterial Artificial Chromosome (BAC)

Back 6

An artificial version of a bacterial chromosome that can be used as a cloning vector to produce many copies of large DNA fragments.

Front 7

BAC Library

Back 7

A collection of all the sequences found in the genome of a species, inserted into bacterial artificial chromosomes (BACs).

Front 8

Bioinformatics

Back 8

The field of study concerned with managing, analyzing, and interpreting biological information, particularly DNA sequences.

Front 9

Open Reading Frame (ORF)

Back 9

Any DNA sequence, ranging in length from several hundred to thousands of base pairs long, that is flanked by a start codon and a stop codon. ORFs identified by computer analysis of DNA may be functional genes, especially if they have other features characteristic of genes.

Front 10

Homology

Back 10

Similarity among organisms of different species due to their inheritance from a common ancestor.

Front 11

Expressed Sequence Tag (EST)

Back 11

A portion of a transcribed gene (synthesized from an mRNA in a cell) used to find the physical location of that gene in the genome.

Front 12

Transposable Elements

Back 12

Any of several kinds of DNA sequences that are capable of moving themselves, or copies of themselves, to other locations in the genome. Include LINEs and SINEs.

Front 13

LINEs (long interspersed nuclear elements)

Back 13

The most abundant class of transposable elements in human genomes; can create copies of itself and insert them elsewhere in the genome.

Front 14

Short Tandem Repeats (STRs)

Back 14

Relatively short DNA sequences that are repeated, one after another, down the length of a chromosome. The two major types are microsatellites and minisatellites.

Front 15

Microsatellite

Back 15

A noncoding stretch of eukaryotic DNA consisting of a repeating sequence one to five base pairs long. Also called simple sequence repeat.

Front 16

Minisatellite

Back 16

A noncoding stretch of eukaryotic DNA consisting of a repeating sequence that is 6 to 500 base pairs long. Also called variable number tandem repeats (VNTRs).

Front 17

Unequal Crossover

Back 17

An error in crossing over during meiosis I in which the two nonsister chromatids match up at different sites. Results in gene duplication in one chromatid and gene loss in the other.

Front 18

Steps that allow an active LINE to transpose

Back 18

1. LINE exists in DNA.

2. RNA polymerase transcribes LINE.

3. LINE mRNA exists nucleus and is translated.

4. LINE mRNA and proteins enter nucleus.

5. Reverse transcriptase makes LINE cDNA from mRNA, then makes cDNA double stranded.

6. Integrase cuts DNA and inserts LINE cDNA.

7. New copy of LINE is integrated into genome.

Front 19

Steps in unequal crossover

Back 19

1. Homologs pair up.

2. Repeats misalign during meiosis I. Crossing over and recombination occur.

3. The products of meiosis are unique and have additional or deleted repeats.

Front 20

DNA Fingerprinting

Back 20

Any of several methods for identifying individuals by unique features of their genomes. Commonly involves using PCR to produce many copies of certain simple sequence repeats (microsatellites) and then analyzing their lengths.

Front 21

Gene Family

Back 21

Genes whose DNA sequences are extremely similar. Thought to have arisen by duplication of a single ancestral gene and subsequent mutations in the duplicated sequences.

Front 22

Gene Duplication

Back 22

The formation of an additional copy of a gene, typically by misalignment of chromosomes during crossing over. Thought to be an important evolutionary process in creating new genes.

Front 23

Pseudogene

Back 23

A DNA sequence that closely resembles a functional gene but is not transcribed. Thought to have arisen by duplication of the functional gene followed by inactivation due to a mutation.

Front 24

Structural Gene

Back 24

A stretch of DNA that codes for a functional protein or functional RNA molecule, not including any regulatory sequences (e.g. a promoter or enhancer).

Front 25

Regulatory Genes

Back 25

DNA sequences that code for regulatory proteins- products that alter gene expression.

Front 26

DNA Microarray

Back 26

A set of single-stranded DNA fragments, representing thousands of different genes that are permanently fixed to a small glass slide. Can be used to determine which genes are expressed in different cell types, under different conditions, or at different developmental stages.

Front 27

Steps in using a DNA microarray

Back 27

1. Isolate mRNAs and use reverse trancriptase to prepare single-stranded cDNA.

2. Make cDNA probes with fluorescent tags.

3. Probe a microarrary.

4. Shine laser light on one spot at a time to induce fluorescence.

Front 28

Transcriptome

Back 28

The complete set of genes transcribed in a particular cell.

Front 29

Proteome

Back 29

The complete set of proteins produced by a particular cell type.

Front 30

Proteomics

Back 30

The systematic study of the interactions, localization, functions, regulation, and other features of the full protein set (proteome) in a particular cell type.

Front 31

Steps in gel electrophoresis

Back 31

1. Load cavities in gel with samples.

2. Hook up power supply and run gel. Molecules separate over time as some migrate faster than others.

3. Remove gel after samples have run its length.

Front 32

Steps in the formation of bands on gels

Back 32

1. Mixture of molecules in a well.

2. As electrophoresis starts, molecule begin to separate by size and charge.

3. Separation increases and molecules with the same size and charge run at the same rate.

4. If each molecule is visualized, the result is a set of bands.