| Abstrakt: |
The female chromosome complement of the thelytokous stick insect Carausius morosus Br. consists of three metacentric sex chromosomes, four metacentric and 57 acrocentric autosomes. The rare impaternate males have two sex chromosomes. The spermatogenesis is highly aberrant which is evident from the various numbers of univalents, homomorphic and unequal bivalents, and multivalents during first metaphase, and from abnormal segregation patterns during first and second anaphase. The abnormalities are due to aneuploidy and structural heterozygosity. The heterozygosity is maintained by the endomeiotic chromosome duplication in females. Translocations resulting from chiasmata in unequal associations are not formed during female meiosis. It has been discussed that the heterozygosity in males, and consequently in females, is caused by either chromosomal mutations, as indicated by at least ten interchanges and three inversions, or hybridization, indicated by allotriploidy. |
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