What's in Your Genome?

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)
February 5, 2013 (reformatted)

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