Haploid chromosomes

Positive results in the mammalian in vivo bone marrow chromosome aberration test indicate that a substance induces stmctural chromosome aberrations in the bone marrow of the species tested. An increase in polyploidy (a multiple of the haploid chromosome number (n) other than the diploid number, i.e., 3n, 4n and so on) may indicate that a substance has the potential to induce numerical aberrations (change in the number of chromosomes from the normal number characteristic of the animals utilized). 

Haploid chromosome number, Wild yeast strains generally have eight (octoploid) or more sets of these chromosomes,... 

Gamete A minute, nucleated protoplasmic reproductive body, usually with a haploid chromosome number, which is capable of uniting with another of like origin to form a new individual. 

Krishanswami and Rangaswami Ayyangar (1935) counted the haploid chromosome number to be 9 in E. indica, 18 in E. coracana, 18 in E. brevifolia, and 17 in . aegyptica, while Bisht and Mukai (2000) counted 36 chromosomes in . coracana, 18 in E. indica and E. tristachya, and 16 in E. multiflora. All these are annuals. For the perennials, E.floccifolia has 18, E. intermedia 18, and . jaegeri 20 chromosomes. Laser flow cytometry was... 

GAMETE A mature germ cell (i.e., a sperm or an egg) possessing a haploid chromosome set and capable of initiating formation of a new organism by fusion with smother gamete. 

Heteroploidy, which is a chromosome complement that is not an exact multiple of the haploid chromosome number, is an in vitro property of most neoplastically transformed cells and many piscine cell lines. This property is sometimes used to criticize cell line research, but while being recognized, should be put into perspective. The differences between neoplastic and normal cells are not profound, otherwise cancer would not be so difficult to comprehend and treat. All experimental approaches come with caveats, with even fish in a tank being an abnormal situation. In the case of... 

Human gametes have 23 chromosomes (haploid chromosome number n = 23), while most somatic cells have 46 chromosomes (diploid chromosome number 2n = 46). 

The answer is e. (Murray, pp 812-828. Scriver, pp 3-45. Sack, pp 57-84. Wilson, pp 123-148.) Aneuploidy involves extra or missing chromosomes that do not arise as increments of the haploid chromosome number n. Polyploidy involves multiples of n, such as triploidy (3n = 69,XXX) or tetraploidy (4n = 92,XXXX). Diploidy (46,XX) and haploidy (23,X) are normal karyotypes in gametes and somatic cells, respectively. A 90,XX karyotype represents tetraploidy with two missing X chromosomes, which has been seen in one patient who had features that resembled those of Turner s syndrome. 

Variation in the amount of nonfunctional DNA in the genomes of various species is largely responsible for the lack of a consistent relationship between the amount of DNA in the haploid chromosomes of an animal or plant and its phylogenetic complexity. 

Telophase I - the homologous chromosome pairs continue to separate. Each pole now has a haploid chromosome set. Telophase I occurs simultaneously with cytokinesis. In animal cells, cleavage furrows form and cell plate appear in plant cells. 

Table 8.7 Karyotypes of 22 M. mucilagina strains (from Table 8.6). Chromosome size from 650 to 2300. Number corresponds to the column in Table 8.6. N haploid chromosome number. Host type abbreviations O Opuntia, C Ferrocactus and S Stenocereinae.

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