ch 20.5-6: biotechnolgy and genomics Flashcards
principles of prokaryotic genomes
- one circular chromosome
- no introns
- many operons
- few regulatory sequences
what do prokaryotic genomes carry?
plasmids: small circular DNA molecules
are genes shared in prokaryotic species?
no, many are not shared
what prokaryotes have large genomes and why?
bacterial species that live in a variety of habitats and have many molecules for food
what prokaryotes have small genomes?
parasitic specials that make use of a host’s biochemical machinery
lateral gene transfer
many genes have been acquired from other species
metagenomics
inventory of all the genes in a community of prokaryotes or ecosystem created by sequencing, analyzing, and comparing the genomes of the component organisms
characteristics of eukaryotic genomes
- larger and more protein-encoding regions
- more regulatory sequences
- most eukaryotic DNA does not encode proteins
- repetitive sequences are derived from transposable elements
what does repetitive DNA explain?
the variation in genome size
transposable elements
DNA segments can move from one place to another within the genome
long interspersed nuclear elements (LINE)
may be derived from retroviruses and they cause mutations by inserting into new sites
gene families
genes are often present in many copies in eukaryotes as a results duplication events
what can happen after duplication?
the original and the copy can be mutated
psuedogene
mutations in one of the gene copies leads to nonfunctional genes
paralogs
genes that arise via duplication
what do two or more paralogs in a genome create?
a gene family
alternative splicing
allows a single gene to code for multiple transcripts and multiple proteins
non coding RNAs
regulate gene expression but do not code for proteins
genomics
have spawned a host of fields called omics
functional genomics
studies how, when, and where all of an organism’s genes are expressed and what they do
DNA microarrays
let researchers study experession of thousands of genes at a time
what can DNA microarrays identify?
which sets of genes are expressed under specific conditions
transcriptomics
sequencing cDNAs so that relative amounts of cDNA is known and can identify which mRNAs are present in particular cell type or in specific condition
proteomics
large scale study of all proteins in cell or organism
