Test for Evolution Without Sex in Bbeloid Rotifers

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Sexual recombination as well as mutations provides the genetically variable raw material upon which evolutionary forces act in higher, more complex organisms. Thus, based upon that assumption, sex has been considered an important, almost necessary, component of the evolutionary process. However, Dr. Matthew Meselson of Harvard University describes a class of animals, Bdelloidea, which, in so far as has been determined, has no sexual genetic exchange. But, as he points out, sexual exchange may occur under rare or at least unknown circumstances and a more rigorous test is needed to confirm the fact that an organism which has been successful in evolution is lacking any mechanism for genetic exchange. He proposes to use restriction fragment length polymorphisms (RFLP) as a test. Specific species of Bdelloidea, thought to be diploid, will be selected as test organisms. Isolated DNA will be fragmented with restriction enzymes and the extent of heterozygosity will be determined. The underlying assumption is that sexual organisms homozygous their chromosomes much more rapidly than do asexual organisms. The project can be done within the one year limitation and is high risk in that if the answer is that there is little heterozygosity seen in the rotifer DNA, the organisms probably have some type of sexual mechanism and thus, are of little interest for further study. If, on the other hand, the answer is that there is a large amount of heterozygosity in their DNA, then significant insights into our understanding of evolution can be achieved by asking the proper questions.*** //