Makałowski W
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20892-6510, USA.
Acta Biochim Pol. 2001;48(3):587-98.
Genetic information of human is encoded in two genomes: nuclear and mitochondrial. Both of them reflect molecular evolution of human starting from the beginning of life (about 4.5 billion years ago) until the origin of Homo sapiens species about 100,000 years ago. From this reason human genome contains some features that are common for different groups of organisms and some features that are unique for Homo sapiens. 3.2 x 10(9) base pairs of human nuclear genome are packed into 23 chromosomes of different size. The smallest chromosome - 21st contains 5 x 10(7) base pairs while the biggest one -1st contains 2.63 x 10(8) base pairs. Despite the fact that the nucleotide sequence of all chromosomes is established, the organisation of nuclear genome put still questions: for example: the exact number of genes encoded by the human genome is still unknown giving estimations from 30 to 150 thousand genes. Coding sequences represent a few percent of human nuclear genome. The majority of the genome is represented by repetitiVe sequences (about 50%) and noncoding unique sequences. This part of the genome is frequently wrongly called "junk DNA". The distribution of genes on chromosomes is irregular, DNA fragments containing low percentage of GC pairs code lower number of genes than the fragments of high percentage of GC pairs.
核基因组和线粒体基因组。它们都反映了从生命起源（约45亿年前）到约10万年前智人物种起源的人类分子进化过程。因此，人类基因组包含一些不同生物群体共有的特征以及一些智人特有的特征。人类核基因组的3.2×10⁹个碱基对被包装成23条不同大小的染色体。最小的染色体——第21号染色体含有5×10⁷个碱基对，而最大的染色体——第1号染色体含有2.63×10⁸个碱基对。尽管所有染色体的核苷酸序列已经确定，但核基因组的组织仍然存在问题：例如，人类基因组编码的基因的确切数量仍然未知，估计在3万到15万个基因之间。编码序列仅占人类核基因组的百分之几。基因组的大部分由重复序列（约50%）和非编码独特序列组成。基因组的这一部分经常被错误地称为“垃圾DNA”。基因在染色体上的分布是不规则的，含GC对比例低的DNA片段编码的基因数量比含GC对比例高的片段少。
