Posted on Mar 05, 2020, 7 p.m.
Scientists from Uppsala University are proposing an addition be made to the theory of evolution that may help to explain why and how genes move around on chromosomes, their hypothesis is called the SNAP Hypothesis and it has been published in the journal PLOS Genetics.
Life on earth is said to have originated around 4 billion years ago and blossomed into a vast and diverse array of species. Together with DNA the Theory Of Evolution can provide detail on replication, mechanisms, and how DNA mutations can occur from generation to generation to help individuals better adapt to the environment. Gradually this has led to the separation of organisms into the variety of species inhabiting all of the ecosystems on the planet.
Current theories explain how genes can mutate over time to acquire new meanings. The big biology mystery remains how relative locations of genes on chromosomes also change over time. Apparently genes have been changing locations since the origin of life, but inquiring minds would like to know how and why genes move their relative locations.
The SNAP Hypothesis is based on the observation that tandem duplications of sections of chromosomes occur frequently in bacteria, and these duplications are lost spontaneously unless they are selected. Selection to maintain a duplication can occur when in sub-optimals environments where having 2 copies of a particular gene may increase fitness.
Duplications can contain hundreds of genes even if only one is selected to maintain. In this hypothesis Diarmid Hughes and Gerrit Brandis suggest that mutations can accumulate quickly in the hundreds of genes that are not selected including those that are normally key when there is only a single copy. Once two different key genes are activated one in each copy of the duplications, these duplications can no longer be lost and from that point on the bacteria will have many genes unnecessarily duplicated, and mutations wo inactivate/delete them will be positively selected because they increase fitness.
All of the unnecessary duplicated genes may be lost by mutation over time, happening at random in each copy of the duplication. The process of random loss of unnecessary duplicated genes in each copy of the the duplication, the relative order of the remaining genes can be completely changed. The SNAP Hypothesis process can rearrange gene order rapidly and it may contribute to separating different species.
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