Search results for "Sex Chromosomes"
showing 10 items of 12 documents
Analysis of chromosomal abnormalities in testicular and epididymal spermatozoa from azoospermic ICSI patients by fluorescence in-situ hybridization
2003
BACKGROUND: An increased incidence of numerical chromosomal abnormalities has been reported in the ejaculated spermatozoa of infertile patients. However, there are few cytogenetic studies of testicular and epididymal spermatozoa, and their results are still controversial. METHODS: Fluorescence in-situ hybridization (FISH) analysis of chromosomes 13, 18, 21, X and Y was performed on seven testicular samples and two epididymal samples from patients with obstructive azoospermia (OA), and on 13 testicular samples from patients with non-obstructive azoospermia (NOA). Five ejaculated sperm samples from normozoospermic fertile donors were evaluated as a control group. RESULTS: Both epididymal sper…
X-inactivation pattern in three cases of X/autosome translocation.
1978
We describe an X/15 translocation which was balanced in a phenotypically normal mother [46,X,t(X;15)(p22;q15)] and unbalanced in her phenotypically abnormal daughter [46,X,der(X),t(X;15)(p22;q15)mat]. A third case involves a balanced X/21 translocation in a girl with a multiple congenital anomaly-retardation syndrome [46,X,t(X;21)(p11;p11?)]. 5-BrdU acridine orange banding on lymphocytes revealed late replication of the normal X chromosome in the mother and of the normal or abnormal X chromosome in the two other cases. Our findings are only partially consistent with previous observations. All X-inactivation patterns can be explained by random inactivation and subsequent selection against sp…
Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.
2003
Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screenng in specific invitro fertilization (IVF) patient groups, along with FISH analysis of spematozoa in intertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 y…
Eradicating Mosquitoes using Translocations: a First Field Experiment
1972
THEORETICAL considerations have led to the assumption that chromosomal translocations with ensuing semisterility could be used to control pests1–3. Inversions could have the same effect in animals and plants in which crossing over occurs in both sexes4. Many translocations of different type and with various degrees of sterility have been produced in the mosquito Culex pipiens5–8. Preliminary laboratory experiments with these translocations have shown that a cage population can be diminished and finally exterminated after a few generations by the release of translocation heterozygotes into the population9.
Genomic characterization of the Atlantic cod sex-locus
2016
AbstractA variety of sex determination mechanisms can be observed in evolutionary divergent teleosts. Sex determination is genetic in Atlantic cod (Gadus morhua), however the genomic location or size of its sex-locus is unknown. Here, we characterize the sex-locus of Atlantic cod using whole genome sequence (WGS) data of 227 wild-caught specimens. Analyzing more than 55 million polymorphic loci, we identify 166 loci that are associated with sex. These loci are located in six distinct regions on five different linkage groups (LG) in the genome. The largest of these regions, an approximately 55 Kb region on LG11, contains the majority of genotypes that segregate closely according to a XX-XY s…
H-Y antigen in the teleost.
1979
H-Y antigen, presumably the product of mammalian testis-determining genes, has been detected in three species of teleost fish, Xiphophorus maculatus, Haplochromis burtoni, and Oryzias latipes, and in hybrids of the genus Tilapia. In X. maculatus H-Y was most readily detected in YY males, suggesting that a genetic determinant of H-Y antigen expression may exist on the teleost Y-chromosome. Although H-Y was detected in males and not in females in each of the species that we studied, male heterogamety has not been firmly established for H. burtoni. Thus despite the extreme phlyogenetic conservation of H-Y genes and their association with the Y-chromosome, it remains open to question whether H-…
Distribution of heterochromatin on the mitotic chromosomes of Musca domestica L. in relation to the activity of male-determining factors
1998
In the housefly, male sex is determined by a dominant factor, M, located either on the Y, on the X, or on any of the five autosomes. M factors on autosome I and on fragments of the Y chromosome show incomplete expressivity, whereas M factors on the other autosomes are fully expressive. To test whether these differences might be caused by heterochromatin-dependent position effects, we studied the distribution of heterochromatin on the mitotic chromosomes by C-banding and by fluorescence in situ hybridization of DNA fragments amplified from microdissected mitotic chromosomes. Our results show a correlation between the chromosomal position of M and the strength of its male-determining activity…
Evidence for male XO sex-chromosome system in Pentodon bidens punctatum (Coleoptera Scarabaeoidea: Scarabaeidae) with X-linked 18S-28S rDNA clusters
2004
In scarab beetle species of the genus Pentodon, the lack of analysis of sex chromosomes in females along with the poor characterization of sex chromosomes in the males, prevented all previous investigations from conclusively stating sex determination system. In this study, somatic chromosomes from females and spermatogonial chromosomes from males of Pentodon bidens punctatum (Coleoptera: Scarabaeoidea: Scarabaeidae) from Sicily have been analyzed using non-differential Giemsa staining. Two modal numbers of chromosomes were obtained: 2n = 20 and 19 in females and males, respectively. This finding along with other karyological characteristics such as the occurrence of one unpaired, heterotypi…
A high incidence of meiotic silencing of unsynapsed chromatin is not associated with substantial pachytene loss in heterozygous male mice carrying mu…
2009
Meiosis is a complex type of cell division that involves homologous chromosome pairing, synapsis, recombination, and segregation. When any of these processes is altered, cellular checkpoints arrest meiosis progression and induce cell elimination. Meiotic impairment is particularly frequent in organisms bearing chromosomal translocations. When chromosomal translocations appear in heterozygosis, the chromosomes involved may not correctly complete synapsis, recombination, and/or segregation, thus promoting the activation of checkpoints that lead to the death of the meiocytes. In mammals and other organisms, the unsynapsed chromosomal regions are subject to a process called meiotic silencing of…
Karyological studies in Coris julis (Pisces, Labridae).
1988
In the present investigation the diploid number 2n = 48 (NF = 58) has been determined for females, primary males, and secondary males of Coris julis from the Gulf of Palermo. Differentiated sex chromosomes have not been observed in the population under study.