(Jan 2015 Ensembl73 assembly)
The complete genome of Drosophila melanogaster
comprises 143.73 Mbp (million base pairs), arranged on
five chromosomes (X, 2, 3, 4,
& Y) and the extranuclear mitochondrial DNA
(MT).
Chromosomes X, 2, & 3 are quite
large (L & R refer to their long and
short arms), Chromosome 4 is a dot. The Y
chromosome has a very small number of genes that pertain to
sex determination. The mtDNA encodes proteins used in
cellular metabolism in the mitochondria. Ribosomal
rDNA genes are clustered in a tandem array on
the short arm of Chromosome 2, where they appear
cytologically as the Nucleolus Organizer Region (NOR).
The genome comprises 17,215 genes, distinguished here as protein-coding Open Reading Frames (ORFs). Other genes code for RNA molecules that are not transcribed into protein, and which may serve regulatory functions. Pseudo-genes are gene-like regions, typically similar to known functional genes, but containing internal stop codons, missing bits, or other features that indicate they are nonfunctional.
The genome comprises 17,215 genes, distinguished here as protein-coding Open Reading Frames (ORFs). Other genes code for RNA molecules that are not transcribed into protein, and which may serve regulatory functions. Pseudo-genes are gene-like regions, typically similar to known functional genes, but containing internal stop codons, missing bits, or other features that indicate they are nonfunctional.