Kapitel 9

Question 1

Family of mobile genetic elements that comprises about 10% of the human genome; this short - repetitive sequence is no longer mobile on its own - but requires enzymes encoded by other elements to transpose.

Answer 1

Alu sequence

Question 2

The preservation of gene order and location in the genomes of different species.

Answer 2

conserved synteny

Question 3

Large segment of DNA - 1000 nucleotide pairs or greater - that has been duplicated or lost in an individual genome (compared to the “reference” genome sequence).

Answer 3

copy-number variation (CNV)

Question 4

Differences in sequence that accumulate over time in DNA segments derived from a common ancestral sequence.

Answer 4

divergence

Question 5

Mechanism for the evolution of new genes; in the process - coding sequences from different genes are brought together to generate a protein with a novel combination of domains.

Answer 5

exon shuffling

Question 6

A process by which new genes can form; involves the accidental generation of an additional copy of a stretch of DNA containing one or more genes - followed by an accumulation of mutations that over time can alter the function of either the original or its copy.

Answer 6

gene duplication and divergence

Question 7

A set of related genes that has arisen through a process of gene duplication and divergence.

Answer 7

gene family

Question 8

Cell type in a diploid organism that carries only one set of chromosomes and is specialized for sexual reproduction. A sperm or an egg; also called gamete.

Answer 8

germ cell

Question 9

The lineage of reproductive cells that contributes to the formation of a new generation of organisms - as distinct from somatic cells - which form the body and leave no descendants in the next generation.

Answer 9

germ line

Question 10

see homologous.

Answer 10

homologous gene

Question 11

Process by which DNA is passed from the genome of one organism to that of another - even to an individual from another species. This contrasts with “vertical” gene transfer - which refers to the transfer of genetic information from parent to progeny.

Answer 11

horizontal gene transfer

Question 12

Type of retrotransposon that constitutes 15% of the human genome; also called LINE-1.

Answer 12

L1 element

Question 13

Short segment of DNA that can move - sometimes through an RNA intermediate - from one location in a genome to another; an important source of genetic variation in most genomes. Also called a transposon.

Answer 13

mobile genetic element

Question 14

Long sequence of nucleotides that contains no stop codon; used to identify potential protein-coding sequences in DNA.

Answer 14

open reading frame (ORF)

Question 15

Diagram or “family tree” showing the evolutionary history of a group of organisms or proteins.

Answer 15

phylogenetic tree

Question 16

Change in a single nucleotide pair in a DNA sequence.

Answer 16

point mutation

Question 17

Preservation of a specific nucleotide sequence driven by the elimination of individuals carrying mutations that interfere with its functions.

Answer 17

purifying selection

Question 18

Type of mobile genetic element that moves by being first transcribed into an RNA copy that is reconverted to DNA by reverse transcriptase and inserted elsewhere in the chromosomes.

Answer 18

retrotransposon

Question 19

RNA-containing virus that replicates in a cell by first making a double-stranded DNA intermediate that becomes integrated into the cell’s chromosome.

Answer 19

retrovirus

Question 20

Enzyme that makes a double-stranded DNA copy from a single-stranded RNA template molecule. Present in retroviruses and as part of the transposition machinery of retrotransposons.

Answer 20

reverse transcriptase

Question 21

Form of genetic variation in which one portion of the population differs from another in terms of which nucleotide is found at a particular position in the genome.

Answer 21

single-nucleotide polymorphism (SNP)

Question 22

Any cell that forms part of the body of a plant or animal that is not a germ cell or germ-line precursor.

Answer 22

somatic cell

Question 23

General name for short segments of DNA that can move from one location to another in the genome. Also known as mobile genetic elements.

Answer 23

transposon

Question 24

Particle consisting of nucleic acid (RNA or DNA) enclosed in a protein coat and capable of replicating within a host cell and spreading from cell to cell. Often the cause of disease.

Answer 24

virus

Question 25

Technique by which a mutation can be made at a particular site in DNA.

Answer 25

site-directed mutagenesis