We report the unusual finding of velocardiofacial syndrome (VCF) in an unexplained 46,XX male. A microdeletion of 22q11.2 was confirmed by fluorescence in situ hybridization (FISH) analysis. Routine G-banded chromosome analysis revealed an XX sex chromosome constitution. FISH was performed using the SRY probe and failed to detect hybridization. The sex chromosome status of the patient was furth...

The primary testis-determining function is exerted by a gene in the sex-determining region of the human Y chromosome. This gene is termed the sex-determining factor or TDF. A zinc finger gene, ZFY, residing in this region has been cloned and characterized. It is a candidate for TDF. A challenge to future molecular research is to clarify the function of a zinc finger gene on the X chromosome, ZF...

Topological indices are numerical parameters of a molecular graph G which characterize its topology. On the other hands, computing the connectivity indices of molecular graphs is an important branch in chemical graph theory. Therefore, we compute First Zagreb index Zg   <span style="font-family: TimesNewRomanPS-Italic...

a total number of 66 chorionic villus samples were cytogenetically investigated. the samples consisted of 30 experimental cvs from spontaneously aborted materialand 36 from live gestations.80% of the samples were successfully grown, of the 30 cases 40% (12) and 33% (10)contained a normal female and a normal male karyotype, respectively, 3.3% (1) and3.3% (1) had abnormal karyotypes (47,xx, + 21;...

Three key steps in meiosis allow diploid organisms to produce haploid gametes: (1) homologous chromosomes (homologs) pair and undergo crossovers; (2) homologs segregate to opposite poles; and (3) sister chromatids segregate to opposite poles. The XX/XO sex determination system found in many nematodes [1] facilitates the study of meiosis because variation is easily recognized [2-4]. Here we show...

The developmental fate of primordial germ cells in the mammalian gonad depends on their environment. In the XY gonad, Sry induces a cascade of molecular and cellular events leading to the organization of testis cords. Germ cells are sequestered inside testis cords by 12.5 dpc where they arrest in mitosis. If the testis pathway is not initiated, germ cells spontaneously enter meiosis by 13.5 dpc...

Biological mechanisms leading to the development of males and females are extremely varied. In the XX/XY system, the male has an unequal pair of chromosomes, while in the ZZ/ZW system, the unequal pair is in the female. Sex can also be determined by the temperature of incubation. Recent research has focused on the identification of sex-determining genes, culminating in the demonstration that th...

Although the sex-determining gene SRY/Sry has been identified in mammals, homologues and genes that have a similar function have yet to be identified in nonmammalian vertebrates. Recently, DMY (the DM-domain gene on the Y chromosome) was cloned from the sex-determining region on the Y chromosome of the teleost fish medaka (Oryzias latipes). DMY has been shown to be required for the normal devel...

  Background and aims: <span style="color: #221e1f; font-family: Optima ...