BI 215 Exam 3 Ch 10

autonomous transposons

autonomous transposons

small, selfish genetic elements-transposons-that encode the ability to move themselves around and/or replace themselves within the genome

bacteriophage

small viruses that infect and reproduce within bacteria

centromere drive

selection at the level of the chromosome that favors mutations to centromeres that increase their chance of segregating to the oocyte instead of to the polar bodies

codon usage bias

a bias in which certain codons occur more frequently than others that specify the same amino acid

conjugation

a process of horizontal gene transfer by which a donor bacterium passes a copy of a plasmid to a recipient bacterium

C-value paradox

the observation that differences in genome size measured in base pairs do not correlate with the phenotypic complexity of an organism

evolutionary genomics

the study of how the composition and structure of genomes have evolved and are evolving

GC content

the fraction of nucleotides in a gene, chromosome, or genome that are G or C rather than A or T

G-value paradox

the observation that despite seemingly large differences in organismal complexity, multicellular eukaryotes tend to have very similar numbers of protein-coding genes

halotype blocks

stretches of the genome where recombination is infrequent and linkage disequilibrium is high

horizontal gene transfer (lateral gene transfer)

the transfer of genetic material from one organism to another organism that is not its offspring

LINE-1 elements

long interspersed elements; a common class of transposable elements, these autonomous transposons make up approximately 17% of the human genome

mobile genetic elements

inessential or accessory genetic elements that can be horizontally transferred among genomes; these include plasmids, prophages, and transposons

nonautonomous transposons

small, selfish genetic elements-transposons-that do not encode the genes necessary to catalyze their own movement and replication, but instead rely on the presence of autonomous transposons for these purposes

noncoding DNA

DNA that does not specify an expressed product such as a protein, tRNA, or mRNA

nuclear genome

the set of chromosomes contained in the eukaryotic nucleus

plasmids

circular extrachromosomal genetic elements common in bacteria and some other microorganisms

prophage

a viral genome that inserts itself into bacterial chromosomes; ___ can subsequently be excised from the genome and initiate viral replication within the bacterial cell

recombination hotspots

small regions of the genome that are particularly prone to serving as locations of crossover

selfish genetic elements

stretches of DNA, such as transposons, that act primarily to ensure their own survival and replication within a genome, even at a fitness cost to the organism

SINE elements

short interspersed elements; a common class of transposable elements in humans, these nonautonomous transposons are incapable of independent replication but rather rely on genes encoded by autonomous transposons elsewhere in the genome

transcription factors

proteins that bind to DNA and influence gene expression

transduction

horizontal gene transfer that occurs when a bacteriophage packages host DNA into its capsule; if that DNA is injected into a new host, it can be incorporated into the genome

transformation

horizontal gene transfer that occurs when a bacterial cell picks up free DNA from the environment and incorporates this DNA into its genome

transposable element

a self-replicating genetic unit that can move or copy itself within a genome

virulence factors

specialized genes that assist bacteria in exploiting eukaryotic hosts