The Forbes sea star and common sea star are broadcast spawners that are known to hybridize, yet they exist as separate, genetically distinct species (unique branches on the tree of life). One mechanism that may contribute to their uniqueness is prezygotic reproductive isolation, which is the incompatibility of gametes (sperm and eggs) from separate species. We know they hybridize, so the eggs and sperm are compatible, but could gametes from the different species be less compatible than the gametes from each individual species? Harper & Hart (2005) addressed this question in a series of cross-fertilization experiments. Did they find evidence that gametes ‘preferred’ to cross with gametes of the same species? Explain your answer.
Genetic Recombination
Recombination is crucial to this process because it allows genes to be reassorted into diverse combinations. Genetic recombination is the process of combining genetic components from two different origins into a single unit. In prokaryotes, genetic recombination takes place by the unilateral transfer of deoxyribonucleic acid. It includes transduction, transformation, and conjugation. The genetic exchange occurring between homologous deoxyribonucleic acid sequences (DNA) from two different sources is termed general recombination. For this to happen, an identical sequence of the two recombining molecules is required. The process of genetic exchange which occurs in eukaryotes during sexual reproduction such as meiosis is an example of this type of genetic recombination.
Microbial Genetics
Genes are the functional units of heredity. They transfer characteristic information from parents to the offspring.
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