Lecture 12 Flashcards
What are single copy genes?
Unique sequences in the genome that code for a protein:
receptors, enzymes, hormones, structural cellular elements, etc
What are multigene families?
Genes with similar functions that have arisen by gene duplication
Explain classic gene families and gene superfamilies?
Classic - multicopy genes that show a high degree of homology
superfamilies: multicopy genes with similar function but limited gene homology
What is the purpose of extragenic DNA?
makes up majority of our DNA (junk DNA)
transcriptionally inactive
might play a part in gene regulation
What are the types of DNA variation?
- SNP (single nucleotide polymorphism)
- SSR (simple sequence repeat)
- VNTR
- LCR (low copy repeat)
Explain SNPs
most do not have an associated phenotype
1 percent = common variation
Explain SSRs
These are tandem repeats of 2, 3 or 4 bp, repeated many times
helpful in forensics and paternity testing
LCR?
these are normally large sequences
may lead to mispairing in meiosis and mitosis
Talk about Long Interspersed Nuclear Elements (LINEs ~6000 base pairs)
found in large amounts in eukaryotes
they are able to make RNA and they include a gene for reverse transcriptase
LINES can copy themselves due to the enzyme
could lead to mutation
Talk about Short interspersed nuclear elements (SINEs)
short sequences (10% of the genome)
Does not have a Reverse transcriptase, thus must use LINEs
Most common SINE is the Alu sequence
What are pseudogenes?
Sequences that look like real genes but are not functional
Where do mitochondria come from (which parent)?
Mother
more prone to mutation
What is a Metacentric chromosome?
p and q arms are of equal length. (chromosome 1)
What is a Submetacentric chromosome?
p arm is shorter than the q arm (chromosome 4)
what is an Acrocentric chromosome
p arm contains little genetic info (chromosomes 13, 14, 15, 21, 22)
