The HIV retrovirus, in particular, is a single-stranded RNA virus that duplicates itself in a host cell by converting its genetic code into double-stranded DNA that is then inserted into the host cell.

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The host cell has no idea that its genetic code (which it generally needs to produce new, healthy cells) has been hijacked, for a long time at least, until the code has been copied and read to reproduce the virus many, many times by the host cell.

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But new research found that, like stem rust, stripe rust increases its genetic variability by reproducing sexually on the leaves of another host plant (the barberry), making itself more adaptable and more deadly.

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Studying how the parasite interacts with its insect host is difficult, he said, because the mosquito's biochemical and genetic make-up are not well defined.

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Four of the genetic substitutions were in hemagglutinin, a protein on the surface of H5N1 that helps it to enter host cells.

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This means there are relatively few genetic combinations amongst them, and this makes them an ideal population for finding genes that cause a whole host of common disorders.

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