Cytogenetic and Genome Research

Gartler, S.M.; Burt, Barbara

doi: 10.1159/000129846pmid: 14319240

A study of chromosome replication in an established bovine male cell line (MDBK) is presented. In this line the Y chromosome is no longer present as an independent structure and a new marker chromosome is present. Morphological evidence suggests that this marker chromosome may have resulted from a fusion of the Y and a large acrocentric chromosome. Chromosome replication studies show that the suspected Y part of the marker chromosome has a DNA replication pattern very similar to that of the Y chromosome in normal cells.

Taft, P.D.; Dalal, K.P.; McArthur, J.W.; Worcester, J.

doi: 10.1159/000129847pmid: 14319241

Sex-chromatin body size was estimated in seven normal women and in four patients with known X chromosome abnormalities by multiplying the length and breadth of 50 bodies in a buccal smear, as measured by a micrometer ocular. The area of the sex-chromatin body proved to be directly proportional to the size of the X chromosome as noted in the karyotype; in cases with an iso-X chromosome the sex-chromatin bodies were significantly larger than in the pooled normal controls; in cases of presumptive deletions they were significantly smaller. Measurements obtained by this simple technique agree closely with those obtained planimetrically. They are more trustworthy than visual impressions by observers lacking wide experience in cytologic interpretation and, in borderline cases, may have value in pointing to a need for determination of the karyotype.

Klinger, H.P.; Lindsten, J.; Fraccaro, M.; Barrai, I.; Dolinar, Z.J.

doi: 10.1159/000129848pmid: 14319242

Sex chromatin deoxyribonucleic acid (SC/DNA) content (determined by Feulgen-photometry) was higher in cultured cell nuclei derived from five women with presumptive iso-chromosomes for the long arm of the X than from five normal women. The mean SC/DNA values from subjects with deleted long arm or short arm iso-chromosome X; deletion of the short arm of X and from lymph node cultures of a subject with a ring X were significantly lower than the control values. SC/DNA from subjects with XY/XXY, XXXY and XXXXY sex chromosome constitutions did not differ from control values. In oral mucosa nuclei the mean SC/DNA and sex chromatin area from the subjects with structurally abnormal X’s also showed a correlation between X chromosome size and SC/DNA or SC/area but in this technically less suitable tissue variability was greater and the differences not statistically significant. These findings indicate that: 1. Only one X chromosome forms sex chromatin. 2. When a structural abnormality of the X is present it is always the abnormal one which becomes positively heteropycnotic. 3. It is probably all, or at least the major portion of the X which forms sex chromatin. 4. The multiple sex chromatin bodies formed in cells with supernumerary X’s contain average amounts of DNA. 5. Visual impression of sex chromatin “size” (staining intensity and area integrated) can be confirmed objectively.

Ohno, S.; Stenius, C.; Faisst, E.; Zenzes, M.T.

doi: 10.1159/000129849pmid: 14319238

Four age groups of the rainbow trout (Salmo irideus) were surveyed in an extensive cytological study. While the basic diploid complement of this species was found to consist of 104 chromosome arms, some elements united and dissociated early in embryonic life; thus within each individual fish, from two to seven distinct chromosome constitutions were identified, ranging from 2n = 58 to 2n = 65. Each somatic cell type tended to have a particular diploid chromosome number. Several multivalents were found in meiotic germ cells of both sexes. The Robertsonian type of chromosomal change which played an important part in the evolution of terrestrial vertebrates is seen within single individuals of this teleost fish.

Soukup, Shirley W.; Takacs, Eva; Warkany, J.

doi: 10.1159/000129850pmid: 14319239

A study was made of chromosome changes in rat embryos after exposure to teratogenic doses of x-rays. Two methods were used for chromosome analysis: a direct method permitting analysis of chromosomes soon after removal of the embryos from the uterus, and a method in which the embryonic cells were first grown in tissue culture for several days after removal, before they were processed. The direct method proved superior to the tissue culture method for demonstrating early chromosome changes. A half day after irradiation a high incidence of chromosomal aberrations was found which dropped rapidly and returned to almost normal values after several days.