KARYOLOGICAL STUDY OF SOME ACARI AND THE PROBLEM OF SEX DETERMINATION IN THE GROUP,
Abstract
The karyologic peculiarities of the sperm cells of four Tyroglyphoid mite species was investigated. The following karyotypes were found: in Glycyphagus domesticus (fam. Glycyphagidae) eight bivalents + X-chromosome; in Tyroglyphus farinae and Tyrophagus noxius (fam. Tyroglyphidae, subfam. Tyroglyphinae) corresponding eight bivalents + X-chromosome and seven bivalents + X-chromosome were established. Thus, in these three species the male sex must be regarded as heterogametic, and sex determination in them most probably belongs to the Protenor-type. There are ten spermatogonial chromosomes and five bivalents in spermatocytes of Rhizoglyphys echinopus (fam. Tyroglyphidae, subfam. Rhizoglyphinae). Sex chromosomes are absent here. In Ixodes ricinus (Ixodidae), spermatocytes increases greatly in size during the 'prolonged growth' period, and it is also at this stage that the nucleus passes the phase of the 'germinal vesicle'. The spermatogonia show the diploid number of 2n=28 chromosomes (26+ X + Y), but in the spermatocytes the haploid number is n=14 (13 + XY). The chromosomes are large and differ greatly in size and configuration. The XY pair represents the smallest pair, and the X exceeds the Y-chromosome by two or three times in length. Their first division is reductional and the second equational. Sex determination belongs to the Lygaeus type. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1968
- Accession Number
- AD0671657
Entities
People
- I. I. Sokolov
Organizations
- United States Army Biological Warfare Laboratories