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Chromosomes of Nigerian Onchocerca volvulus were compared with those of Guatemalan O. volvulus. Both parasites had basically the same chromosomal construct (2n = 8, XY type). Autosomes consisted of a pair of large and two smaller pairs. Sex chromosomes were made up of medium sized X chromosome and very small Y chromosome. It was not possible to infer the position of the centromeres.
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Hirai et al. (1987) studied this question.
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