Vertebrate Evolution Driven by DNA from Infectious Organisms

A prior post listed 5 assertions regarding the role of infectious organisms on the human genome. In the next few blogs we ' ll look at each assertion, in excerpts fromPrecision Medicine and the Reinvention of Human Disease. Here ' s the second:Some of the key steps in the development of vertebrate animals, and mammals in particular, have come from DNA acquired from infectious organisms. Thehuman genome has preserved its viral ballast, at some cost. At every cell division, energy is expended to replicate the genome, and the larger the genome, the more energy must be expended. Why do we spend a large portion of the energy required to replicate our genome, on inactive sequences, of viral origin? Why doesn ’t our genome simply eject the extra DNA, a biological process that is commonplace in the evolution of obligate intracellular parasitic organisms? Maybe it ' s because we use viral genes to our own advantage. Two evolutionary leaps, benefiting the ancestral classes of humans, and owed to the acquisition of viral genes, include the attainment of adaptive immunity and the development of the mammalian placenta. Let ’s take a moment to see how these innovations came about. Adaptive immunity evolved at about the same time that jawed vertebrates first appeared on earth. The crucial gene responsible for the great leap to adaptive immunity, the recombination activating gene (RAG), was stolen from a retrovirus. To understand the pivotal evolutionary role of RAG, we need to review a ...
Source: Specified Life - Category: Information Technology Tags: evolution precision medicine viral virus Source Type: blogs