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Hello students.
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The question given is which of the following models of speciation hinges on a physical barrier which prevents the gene flow between populations? so let us start answering.
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The hybrid speciation which is given in option c, hybrid speciation which has been given to us in option c is the correct answer because hybrid speciation between speciesiation.
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Species as viruses, it can transfer genes between species.
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It can transfer genes between species.
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And the bacteria, they can incorporate genes from other dead bacteria, exchange the genes within the living bacteria and can exchange plasmids across the species boundaries.
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The sequence comparison, the sequence comparison, it suggests recent horizontal transfer of many genes among diverse species, including across the boundaries, including the boundaries of the phylogenetic domains, thus determining the phylogenetic history of a species cannot be done.
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And conclusively by determining the evolutionary trees for a single gene.
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Therefore, option c is the correct answer for the given question.
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Moving ahead, answering the next question that has been given, it asks, sympathic species with matching chromosome numbers are rare, and we have to tell why is this possible.
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So, let us answer...