sodium-ethylxanthate and Chromosome-Inversion

The frog Rana rugosa uniquely possesses two different sex-determining systems of XX/XY and ZZ/ZW, separately in the geographic populations. The sex chromosomes of both types share the same origin at chromosome 7, and the structural differences between X and Y or Z and W were evolved through two inversions. In order to ascertain the mechanisms of degeneration of W and Y chromosomes, we gynogenetically produced homozygous diploids WW and YY and examined their viability. Tadpoles from geographic group N (W(N)W(N)) containing three populations died of edema at an early developmental stage within 10 days after hatching, while tadpoles from the geographic group K (W(K)W(K)) that contained two populations died of underdeveloped growth at a much later stage, 40-50 days after fertilization. On the contrary, W(N)W(K) and W(K)W(N) hybrid embryos were viable, successfully passed the two lethal stages, and survived till the attainment of adulthood. The observed survival implies that the lethal genes of the W chromosomes are not shared by the two groups and thus demonstrates their independent degeneration histories between the local groups. In sharp contrast, a sex-linked gene of androgen receptor gene (AR) from the W chromosome was down-regulated in expression in both the groups, suggesting that inactivation of the W-AR allele preceded divergence of the two groups and appearance of the lethal genes. Besides, the YY embryos died of cardiac edema immediately after hatching. The symptom of lethality and the stage of developmental arrest differed from those for either of WW lethal embryos. We therefore conclude that the W and Y chromosomes involve no evolutionary common scenario for degeneration.

Topics: Animals; Chromosome Inversion; Diploidy; Embryo, Nonmammalian; Embryonic Development; Female; Male; Mutation; Ranidae; Receptors, Androgen; Sex; Sex Determination Processes; Y Chromosome

In this report, we present the overall sexual function and clinical features of patients with Klinefelter's syndrome with the chief complaint of male infertility. The study consisted of 40 patients with a control group of 55 infertile non-azoospermic males with a normal 46,XY karyotype who visited the Reproduction Center of Toho University Hospital during the 5.5-year period between January 1991 and June 1996 with the chief complaint of male infertility. Among the 40 patients with Klinefelter's syndrome, 38 cases were pure 47,XXY, one case was 47,XXY with a pericentric inversion of chromosome 9 and one case was a mosaic of 46,XY/47,XXY(2:28). Thirty-nine of these 40 patients were azoospermic and one (47,XXY) had severe oligoasthenozoospermia. The sexual function of the patients was evaluated according to their responses to a preliminary questionnaire devised by our department. There was no significant difference in the frequency of sexual function disturbances between the patients with Klinefelter's syndrome and the control group (67.5% vs. 60.0%; chi 2 analysis; p = 0.454). The mean frequency of sexual intercourse per month in the patients with Klinefelter's syndrome was significantly higher than in the control group (4.4 +/- 2.8 vs 3.3 +/- 1.6: Welch's t-test, p < 0.05). A possible explanation for this variation may lie in the fact that many of these patients were diagnosed with azoospermia poor to the administration of the questionnaire and may have wished to continue to have relations as a couple.

Topics: Adult; Chromosome Inversion; Chromosomes, Human, Pair 9; Ejaculation; Follicle Stimulating Hormone; Humans; Infertility, Male; Karyotyping; Klinefelter Syndrome; Libido; Luteinizing Hormone; Male; Orgasm; Penile Erection; Prolactin; Semen; Sex; Sexual Behavior; Surveys and Questionnaires; Testis; Testosterone

For technical reasons studies of chiasma frequency and distribution, and hence of intrachromosomal recombination, have mostly been confined to male meiosis. However, there is now sufficient comparative data on male and female meiosis, in both plants and animals, to show that the extent of intra-chromosomal recombination in some organisms may be much the same on the female as on the male side, whereas other organisms show extreme sexual divergence in this regard. The evolutionary significance of such diversity remains enigmatic.

Topics: Animals; Biological Evolution; Chromosome Inversion; Chromosomes; Crossing Over, Genetic; Female; Hot Temperature; Male; Meiosis; Plant Cells; Recombination, Genetic; Sex

Topics: Animals; Chromosome Inversion; Chromosomes; Crossing Over, Genetic; Drosophila; Drosophila melanogaster; Research; Sex; X Chromosome