Genomes and Evolution Flashcards
genomics
study of gene seq., mechanisms that regulate gene activity, interaction between genetic factors and btw. genetic and non-genetic factors, comparisons btwn species
genome
organism’s entire DNA/RNA; organisms’s entire collection of genes
genetic map
units are recombination frequency (Rf), centiMorgans (cM) or map units (m.u.); came first: only need to know seq. of 2 elements
physical maps
units are basepairs (bp) show distances btwn genes more clearly; made using enzymes to cut DNA into fragments inserting fragments into vectors and sequencing fragments; vectors bind certain set of PCR primers next to insertion site; overlapping clones = success
recombination frequency
diff in diff genders, ethnic groups, drug/chem. exposures; lower near centromere vs. telomere
sampling error
can cause genetic map to position genes improperly if the study had a small population
C Value Paradox
no relationship btwn genome size and organism complexity; more DNA does not mean more complex organism
C value
how much DNA that organism has in diploid cell
complex organism
protein diversity is key
eukaryotic genomes
contain genes and gene families
gene families
large duplications (segmental duplications) occurred during evolution w end result that some genes came from common ancestor but had time to diverge from each other through seq. changes that occurred after duplication
pseudogenes
mutation that renders some copies of gene families nonfunctional
homologs
gene related through evolution
orthologs
homologous genes found in two different species and evolved from common ancestor
paralogs
2 genes w/i single organism that are homologous and arose from duplication sometime in evolutionary past
globin gene family
carry oxygen
unique sequences
found only once in the genome; 30-75% of genome; protein coding genes or regulatory sequences (miRNAs other regulatory RNAs)
highly repetitive DNA
repeated sequences range from 5-300 bp; 5-45% of genome; up to 10,000 copies per genome; often found in heterochromatin at centromeres and telomeres
moderately repetitive DNA
150-300 bp; 1-30% of genome; 10-1000 copies per genome; genes for histone protein, some rRNA and some tRNAs
tandemly repeated sequences
back to back repeats w no intervening sequences
interspersed repeat sequences
scattered throughout the genome often due to action of transposable elements
short interspersed elements (SINEs)
approx. 200-300 bp; most common = Alu repeat (200-300 bp, several million copies per genome)