4.1 Flashcards
Definitions of Gene terms - Genome, Gene, Extragenic DNA,
Genome - set of genetic material of an organism
Gene - DNA required to encode a gene product
Extragenic DNA - does not encode any protein.
Haploid nuclear human genome = 3.2Mb
DNA quantity paradox
Amount of DNA does not equal complexity, number of genes, size and the complexity odes not equal the number of genes.
Introns and Exons
Exons are coding regions of the mRna and are not cleaved during splicing.
Introns are non coding regions of the mRNA and are cleaved during splicing.
Alternative splicing
The generation of different mature RNA transcripts from the same gene.
Extragenic DNA
Non coding RNA
Repetitive DNA sequences - tandem repeats (satellite DNA. Sparse repeats - LINES, SINES, LTR, transposons.
Gene duplication and pseudogenes.
ENCODE
Goal of ENCODE is to build a list of functional elements in the human genome
Noncoding RNA
tRNA and rRNA - play a role in protein synthesis
miRNA - inhibit translation/ stimulate mRNA degradation.
Long non coding RNA - regulators of gene expression
snRNA and snoRNA
Repetitive DNA sequences (Tandem)
Important for the structure of the chromosome.
Of total genome 40% in drosophila and 10% in humans
This is satellite DNA - due to separation of genomic DNA in centrifugation satellite bands appear.
AT rich sequences less dense. GC rich sequences are denser.
Repetitive DNA sequences (Sparse)
Important contributor to genomic size ( 45% of human genome).
SINE = 13%
LINE = 21%
LTR transposons = 8%
DNA transposons = 3%
Gene duplication and pseduogenes
Gene duplication is duplication of a region of DNA that contains at least 1 gene. Two genes code for same protein. groups of genes with similar sequence called gene families.
pseudogenes - functional but inactive copies of genes due to accumulation of mutations
