Genome size diversity and evolution of species

Hamburg

2006

S. 15-37

2 Abb., 3 Tab., zahlr. Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200151611

There is enormous diversity in the genome size in eukaryotes. For example, a small plant Arabidopsis has a genome size of 157 Mb (megabases), as compared to more larger and complex organism as a human with a genome size of 3,000 Mb and a pine tree with a genome size of 20,000 Mb. However, genome size variation far exceeds the estimated numbers of coding genes in these organisms. Therefore, there is a lack of correlation between the genome size and organismal complexity, giving rise to the so-called "C-value paradox". Partial explanation of the C-value paradox has been provided by the presence of differential amounts of the non-coding sequences, particularly transposable elements (TEs), which are a major component of the eukaryotic genomes. However, the TE values vary widely in large genomes, and TEs alone may not account for the genome size variation. Genome size diversity is clearly non-random, and its origins remain elusive. As it turns out, there are a number of other parameters, in addition to TEs that contribute to the overall genome size complexity. These include the G-value or N-value (total number of coding genes), the CS value (chromosome size), the D-value (percentage of duplicate genes), and other genomic components that constitute the genome size.