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The distribution of genes in human genome

Part 2. Genomics

2.3. The Human Genome

Short Specialist Review

  1. Giorgio Bernardi

Published Online: 15 JUL 2005

DOI: 10.1002/047001153X.g203301

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

How to Cite

Bernardi, G. 2005. The distribution of genes in human genome. Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics. 2:2.3:28.

Author Information

  1. Stazione Zoologica Anton Dohrn, Laboratory of Molecular Evolution, Naples, Italy

Publication History

  1. Published Online: 15 JUL 2005

Abstract

The human genome is a mosaic of isochores, long (>300 kb) DNA regions, each one of which is characterized by a low compositional heterogeneity. Isochores belong, however, to a small number of families that cover a very broad GC range (GC is the molar percentage of guanine + cytosine in DNA). An isochore pattern is very widespread in eukaryotes. This pattern (the “genome phenotype”) is stable over geological times, but is different in different vertebrate and plant classes. In all vertebrates, there are good correlations between the GC levels of coding and contiguous noncoding sequences, as well as among the GC levels of different codon positions. Such correlations amount to a “genomic code”.

Gene distribution is bimodal in vertebrates, gene density being very high in the small “genome core” (corresponding in the human genome to the GC-richest isochore families H2 + H3) and very low in the vast “genome desert” (formed by the other isochore families L1, L2, and H1). The gene distribution of vertebrates is correlated with important structural, functional, and evolutionary features.

Keywords:

  • genome organization;
  • genome evolution;
  • vertebrates