Chromosome structure and cytoplasmic genomes

bl2001 astrid

organisation of nuclear DNA

euchromatin

contains genes

less condensed

at chromosome arms

gene rich

heterochromatin

doesn’t contain genes, contains highly repetitive sequences

highly condensed

at centromere and telomeres

gene poor

sources of non coding dna

pseudogenes

introns

tandem repeats

transposable elements

promoter

dna sequence that controls the initiation of rna transcription

aim of human genome project

to build a comprehensive parts list of functional elements in the human genome

what are transposable elements

mobile genetic elements

where do colour mutations in plants come from

from transposons jumping in and out

transcription

DNA to RNA

microsatellites

5 nucleotide repeats throughout genome

minisatelittes

telomeres >6 nucleotide repeats at the end of chromosomes repeated about 2500 times

telomeres

get shorter with age in animals

protects end of chromosomes

prevent chromosomes binding to eachother

main sources of extra dna in animals

retrotransposons

introns

main sources of extra dna in plants

duplications

reterotransposons

nuclear genomes

linear dna molecules

bound to chromosomal proteins (chromatin) to form chromosomes

cytoplasmic genomes

no chromosomal proteins

mitochondria

plastids

plastid

cpDNA

60-100 genes per chromosomes

many copies

mitochondrial

mtDNA

37 genes per chromosome (in human)