Three unique sequences derived from the Y chromosome have been mapped within the human genome. A Y specific sequence DYS20 is localised to Yq11.2. DXYS25 and DXYS27 are both X-Y homologous sequences which map to the Y short arm and to Xq21. DXYS25 maps more distally than DXYS27, on the Y short arm and on the X long arm. Y specific restriction fragments for these two sequences are shown to be pr...

Dosage compensation is the crucial process that equalizes gene expression from the X chromosome between males (XY) and females (XX). In Drosophila, the male-specific lethal (MSL) ribonucleoprotein complex mediates dosage compensation by upregulating transcription from the single male X chromosome approximately twofold. A key challenge is to understand how the MSL complex distinguishes the X chr...

There are two populations of sperm in bull semen. One consists of X-chromosome-bearing sperm; the other consists of Y-chromosome-bearing sperm. In contrast, all cattle ova contain an X chromosome. That is why when an X-chromosome-bearing sperm fertilizes the ovum a female (XX) develops, and when a Y-chromosome-bearing sperm fertilizes the ovum, a male (XY) develops. Ratios of the number of male...

The transgenic insertional mouse mutation Odd Sex (Ods) represents a model for the long-range regulation of Sox9. The mutation causes complete female-to-male sex reversal by inducing a male-specific expression pattern of Sox9 in XX Ods/+ embryonic gonads. We previously described an A/J strain-specific suppressor of Ods termed Odsm1(A). Here we show that phenotypic sex depends on a complex inter...

Cytogenetic analysis of 4 cases of meningiomas from 3 male and 1 female patients is reported. One of male patients suffered from neurofibromatosis type 2. Histologically, the meningiomas were meningotheliomatous (1), transitional (2), and psammomatous (1). Chromosomal abnormalities were found in all cases with a karyotype 45,XY,-22, 45,XY,-16, 45,XX,-2, and 45,XY,t (15p;22q), respectively. Mono...

A candidate gene for sex determination was localized within a 35 kb region of the Y chromosome immediately adjacent to the pseudoautosomal boundary. Here, we describe a study of Sry detection in the gonads of intersex patients including 5 male pseudohermaphrodite (MPH), 4 XX true hermaphrodite (TH) and each 1 mixed gonadal dysgenesis (MGD) and XX sex reversal, and in the clitoris of 3 female ps...

A child with ambiguous genitalia, brought up phenotypically male, had a 46,XX/46,XY karyotype. At laparotomy, he had a left sided ovary and uterus, and a right sided scrotal testis. The 46,XX line made up 50% of cells in the blood and 90% of cells in a skin biopsy. There were no cytogenetic polymorphisms. Analysis of lymphocyte DNA with seven polymorphic DNA markers showed him to be chimaeric, ...

dpy-27 is an essential dosage compensation gene that acts to reduce expression of both hermaphrodite X chromosomes. The DPY-27 protein becomes specifically localized to the X chromosomes of wild-type XX embryos, but remains diffusely distributed throughout the nuclei of male (XO) embryos. In xol-1 mutant XO embryos that activate the XX mode of dosage compensation and die from inappropriately lo...

In a recent opinion article (1), we incorrectly stated that to date no cases of gender dysphoria had been reported in 46,XX individuals with adrenogenital syndrome raised as females. Reflecting on this statement prompted this review. In a review by Dessens et al. in 2005 (2), 13 of 250 (5.2%) cases of females with congenital adrenal hyperplasia (CAH) assigned the female gender role early in lif...

Monochorionic twins are usually monozygotic and thus usually have the same sex. A case of monochorionic diamniotic twins following IVF/ICSI and laser treatment of the zona pellucida ("assisted hatching") is presented in which partial embryo amalgamation appears to have occurred. Discordant sex between the twins was suspected on detailed antenatal ultrasound at 13 + 3 weeks gestation and was con...