genes and genomes Flashcards
how is genomics possible?
next-generation sequencing
How is genomics possible
computational capacity
Definition of a gene
the DNA sequence required to synthesize a product (protein or RNA) important for the function of a cell
Three regions of a gene
- coding sequence
- transcribed, non-coding sequences
- Regulatory sequences
Methods for finding genes(2)
- look for DNA sequences that are usually found in or near genes
- look for molecules produced by genes( RNA, protein)
Steps in identifying gene products
- Isolate cytoplasmic RNA and make a copy DNA (cDNA) of this RNA using reverse transcriptase
- Sequence these cDNAs
- Compare the sequence of these cDNAs with the genome sequence of the organism
Using RNA to make cDNA cannot
show what the encoded gene product does
Genome size in viruses and prokaryotes, but not in eukaryotes
gene numbers correlate with genome size
Gene number variation
varies less than DNA content
Largest portion of the human genome
transposons and not actual coding sequences
Life of the retrovirus
viral RNA changes into DNA and inserts into the host genome
what do retroviruses evolve into when they become defective
retrotransposons
Determine function of new gene: Compare
compare sequence of the gene product to sequences of gene products with known functions
Comparing function of new gene example
CDK
Determine function of new gene: test tube
isolate its products and determine what process this product is able to perform in a test tube
Test tube function of new gene example
hemoglobin binding oxygen
Determine function of new gene: make a mutation
Make a mutation in the gene and see what happens