Karyological analysis of Cylindera trisignata (Latreille & Dejean, 1822) from Portugal (Coleoptera, Cicindelidae)
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- Collares-Pereira, M.J. & Serrano, A.R.M. Genetica (1990) 82: 79. doi:10.1007/BF00124635
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Cellular suspensions of germinal tissues of Cylindera trisignata provided the definition of its karyotype: 2n=23 and 2n=26 for the males and females respectively. This Palearctic species has a sex chromosome system of the X1X2X3X4Y / X1X1X2X2X3X3X4X4 type, only found until now in Cicindela maroccana pseudomaroccana. The heterosomes are not well-differentiated from the general morphological standpoint. To explain the origin of the 4X condition, a mechanism of dissociation of the X chromosomes rather than an incorporation of autosomal segments is proposed. However, based on the occurrence of distinct ploidy levels, both in male and female cells, with a relatively high incidence for the tetraploid condition with regular autosomal bivalents, the hypothesis of a possible evolutionary role of polyploidy is suggested.