The components of the nuclear human genome

The human genome is huge, consisting of 3 billion
base pairs (3!109 bp or 3000 Mb) per haploid
set of chromosomes. Only 30% of mammalian
DNA is related to genes (900 Mb),
whereas 70% of the DNA is not (2100 Mb).
Coding DNA in genes accounts for only 3% (90
Mb) of the total amount of DNA. The bulk of
DNA (70%) consists of sequences that are repeated
many times (repetitive DNA). Characteristic
types of repetitive DNA are tandem repeats.
Depending on their size and pattern,
different types are distinguished: classic satellite
DNA, minisatellites, and microsatellites. Together
they constitute 14% of the total DNA (420
Mb). More than half of human DNA (56%) consists
of repeats interspersed throughout the
genome. The most important types are long terminal
repeats (LTRs), LINEs (long interspersed
nuclear elements), SINEs (short interspersed
nuclear elements), and transposons.