CYTOGENETIC STUDIES FOLLOWING HIGH DOSAGE PATERNAL IRRADIATION IN THE MEALY BUG PLANOCOCCUS CITRI. II. CYTOLOGY OF X$sub 1$ FEMALES AND THE PROBLEM OF LECANOID SEX DETERMINATION
Females of the mealy bug were mated to males previously irradiated with heavy doses of Co/sup 60/ gamma rays (30000 to 120000 rep), the progeny is mostly female. Observations are made on diploid, triploid andd mosaic survivors. These Xi females are gynogenetic, with unbroken chromosomes. Detailed cytology of 17 such gynogenetic females showed triploids, diploids, 3N/2N and 2N/N mosaics. Most of the embryos produced by triploid mothers were aneuploid and these degenerated before gastrulation. Regardless of aneuploidy, male embryos showed the typical lecanoid heterochromatization of the paternal set of chromosomes. Just prior to degeneration, the euchromatic chromosomes in the aneuploid male embryos showed endomitotic splitting while the heterochromatic did not. Among the progeny of triploid female and diploid male matings, only females with five euchromatic plus five heterochromatic chromosomes andd females with 10 or 15 euchromatic chromsomes were found. A search for adults with 5 heterochromatic + 10 euchromatic chromosomes among the progeny of triploid mothers was unsuccessful. Chromosomal variables such as aneuploidy of the euchromatic set, haploidy and fragmentation are discussed in relation to the problems of heterochromatization of the paternal set andd sex determination of this species. (BBB)
- Research Organization:
- Univ. of California, Berkeley
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-005030
- OSTI ID:
- 4162681
- Journal Information:
- Chromosoma (West Germany), Vol. Vol: 14; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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