The total size of the human genome is estimated to be 3.2 × 109 bp [How Big Is the Human Genome?]. Here are the major components.
Transposable Elements: (44% junk)
DNA transposons:
active (functional): <0.1%
defective (nonfunctional): 3%
retrotransposons:
active (functional): <0.1%
defective transposons
(full-length, nonfunctional): 8%
L1 LINES (fragments, nonfunctional): 16%
other LINES: 4%
SINES (small pseudogene fragments): 13%
co-opted transposons/fragments: <0.1% a
aCo-opted transposons and transposon fragments are those that have secondarily acquired a new function.Viruses (9% junk)
DNA viruses
active (functional): <0.1%
defective DNA viruses: ~1%
RNA viruses
active (functional): <0.1%
defective (nonfunctional): 8%
co-opted RNA viruses: <0.1% b
bCo-opted RNA viruses are defective integrated virus genomes that have secondarily acquired a new function.Pseudogenes (1.2% junk)
(from protein-encoding genes): 1.2% junk
co-opted pseudogenes: <0.1% c
cCo-opted pseudogenes are formerly defective pseudogenes those that have secondarily acquired a new function.Ribosomal RNA genes:
essential 0.22%
junk 0.19%
Other RNA encoding genes
tRNA genes: <0.1% (essential)
known small RNA genes: <0.1% (essential)
putative regulatory RNAs: ~2% (essential)
Protein-encoding genes: (9.6% junk)
transcribed region:
essential 1.8%
intron junk (not included above) 9.6% d
dIntrons sequences account for about 30% of the genome. Most of these sequences qualify as junk but they are littered with defective transposable elements that are already included in the calculation of junk DNA.Regulatory sequences:
essential 0.6%
Origins of DNA replication
<0.1% (essential)
Scaffold attachment regions (SARS)
<0.1% (essential)
Highly Repetitive DNA (1% junk)
α-satellite DNA (centromeres)
essential 2.0%
non-essential 1.0%%
telomeres
essential (less than 1000 kb, insignificant)
Intergenic DNA (not included above)
conserved 2% (essential)
non-conserved 26.3% (unknown but probably junk)
Theme
Genomes
& Junk DNATotal Essential/Functional (so far) = 8.7%
Total Junk (so far) = 65%
Unknown (probably mostly junk) = 26.3%
For references and further information click on the "Genomes & Junk DNA" link in the box
LAST UPDATES: May 10, 2011 (fixed totals, and ribosomal RNA calculations)
June 3, 2011 (added total genome size)