Toward a Biology Worthy of Life > Natural Genome Remodeling > Brief excerpt
A project by Stephen L. Talbott

The generation of new genetic material

Quite aside from such contextualization, it has long been known that the organism generates altogether new genetic material by duplicating entire genes, modifying them, and supplying them with regulatory elements. This can occur through direct duplication of genes or even larger chromosomal segments, and also through reverse transcription, whereby messenger RNA molecules, produced from DNA, are transcribed back into new DNA, which can then be modified. But “the array of mechanisms underlying the origin of new genes is compelling, extending way beyond the traditionally well-studied source of gene duplication”, writes Henrik Kaessmann of the Center for Integrative Genomics in Switzerland.

In a broad overview of the relevant studies, Kaessmann documents a dizzying variety of techniques by which the organism diversifies and enlarges its genetic repertoire. For example, two duplicated genes can, via a number of different pathways, fuse into a single chimeric gene. And not only protein-coding RNAs, but also small, regulatory RNAs, can be reverse transcribed into DNA and their functions diversified. And again, various repetitive and mobile elements called “transposons” can move around in the genome, often being duplicated in the process and then co-opted either as new protein-coding genes or new regulatory genes (Kaessmann 2010).

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