Chapter 21 Flashcards
genomics
the study of whole sets of genes and their interactions
bioinformatics
the application of computational methods to store and analyze data
Human Genome Project 1990
Aim- to determine the complete sequence of each chromosome
o This was all 3 billion pairs in a haploid set of human chroms.
Whole-genome shotgun approach
attempt to sequence the human genome by cloning and sequencing DNA fragments from randomly cut DNA
o Computer programs combine these into a continuous sequence
Metagenomics
approach in which DNA from an entire group of species is collected from an environmental sample and sequenced
Gene annotation
when scientists are able to identify all the protein-coding genes in the sequence and their functions
o Involves looking for expressed tag sequences
Expressed sequence tags (Gene annotation)
using a software to scan stored sequences for transcriptional and translational start and stop signals, RNA splicing sites, and other signs of protein coding genes
• This software looks for short sequences that specify known mRNA’s
• Identifies sequences that turn out to be previously unknown protein-coding genes
• Collected from cDNA sequences
Proteomics
the systematic study of proteins and their properties o Proteins (not the genes that encode them) carry out most of the activities in the cell.
Systems biology (defn and uses)
aims to model the dynamic behavior of whole biological systems based on the study of the interactions among a system’s parts
o Used to
• Define gene and protein interaction networks
• Map gene products in specific locations based on the similarity of their interactions
Pseudogenes
former genes that have accumulated mutations over a long time and no longer produce functional proteins
o Single copy, noncoding DNA
repetitive DNA
consists of sequences that are present in multiple copies of the genome
junk DNA
noncoding DNA that neither codes for proteins nor is transcribed to produce RNA’s with known functions
transposable elements
stretches of ‘noncoding’ DNA that can move from one location to another within the genome
o Never completely detach from the DNA
transposition
when a transposable element moves from one site in cell’s DNA to a different target site by a type of recombination
transposons
eukaryotic transposable elements that move within a genome by means of a DNA intermediate
transposase
enzyme encoded by transposon
retrotransposons
move by means of RNA intermediate that is transcript of retrotransposon DNA
• Leave a copy at original site
• RNA intermediate is first converted back to DNA by reverse transcriptase (which is coded by retrotransposon)
Alu elements
transposable element-related DNA which do not code for any protein
o Some Alu elements are transcribed into RNAs which regulate gene expression
simple sequence DNA
contains many copies of tandemly repeated short sequences
o Makes up 3% of human genome
o Ex: GTTAC/ GTTAC/ GTTAC
short-tandem repeat
when a unit contains a set of 2-5 nucleotides
multigene families
groups of genes from the same organism that code proteins with similar sequences
o In MG families consisting of identical DNA sequences, sequences are clustered tandemly and have RNA as final products
o In MG families with nonidentical genes, the different forms of the subunit are expressed at different times during the development, allowing the function of the protein
o Ex. Alpha and beta hemoglobin
polyploidy
accident in meiosis which results in one or more extra sets of chromosomes
exon shuffling
occasional mixing and matching of different exons either within a gene or between two different genes
o Happens as a result of errors in meiotic recombination
o Could lead to proteins with new combinations of functions
highly conserved
genes which have remained similar in distantly related species
