Day 2, Lecture 2: Genetics: Gene structure-function/Transfer of genetic info Flashcards
What is the Splice donor site
5’ GT/GU on the intron
Splice acceptor site
3’ AG on the intron
Splicing is a complex process directed by sequence elements at the
5’ (splice donor) and 3’ (splice acceptor) ends of introns
Which is longer the distance of the splice donor site to the branch site or the distance of the branch site to the splice acceptor site
- The splice to donor site is 10s to > 10,000 nucleotides long
- Branch site to splice acceptor site is < 20 nucleotides long
Role of snRNPs in mediating RNA splicing
genetic code is deciphered on ___ via codon-anticodon recognition
ribsomes
is it always possible to define a gene as a discrete transcriptional unit
- No
- The final product can have different combinations of genes
Alternative splicing
- >50% of human genes use different combinations of exons to produce more than one type of protein.
- A single gene may use different combinations of exons producing more than one type of protein
- May be tissue specific and/or developmental stage specific
Differential gene expression
Genes may be expressed in specific tissues and developmental stages
_____ results in tissue-specific products of the calcitonin gene
Differential RNA processing
Special forms of differential gene expression
- Genetic imprinting
- X-Chromosome inactivation
about how many genes are imprinted
only a minority (about 60)
Does the XIC (X-inactivation center) mediate chromosome counting for activation
- Yes
- it is able to make sure that there is only one active X chromosome per diploid set of autosomes
Heteroplasmy
Each cell may have different numbers of mutant and normal mitochondrial genomes
The mitochondrial genome is composed of
a single compact circular chromosome
The mitochondrial genome is inherited
maternally
How many mitochondrial genes are there
37 genes
