Search results for "chromosome"
showing 10 items of 1175 documents
Mapping of Friedreich's ataxia locus by identification of recombination events in patients homozygous by descent
1994
The Friedreich's ataxia locus (FRDA) maps on chromosome 9q13. Genetic data, obtained from a small number of recombination events, indicated that the FRDA locus might be located centromeric to the D9S15/D9S5 linkage group, the most probable order being cen-FRDA-D9S5-D9S111-D9S15-D9S110-qter. Recently, new centromeric markers have been reported. Analysis of these markers allowed us to localize the recombination breakpoint in some of the recombinant families. However, only one proximal recombination has been found with these markers. To increase the genetic information from FRDA families, we have analyzed the centromeric markers FR1, FR2, FR7, FR8, and FR5 in patients homozygous by descent. Th…
New chromosome numbers for plant taxa endemic to the Balearic Islands
2006
Mitotic chromosome numbers are reported from 25 vascular plant taxa, endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers ofAnthyllis vulneraria subsp.balearica (2n=12),Cymbalaria fragilis (2n=56), andPolygonum romanum subsp.balearicum (2n=40) were determined for the first time. A new chromosome number was found in several populations ofAnthyllis hystrix (2n=70) suggesting that this species is decaploid, in contrast to an earlier work reporting a higher ploidy level (2n=12x=84). The new chromosome number 2n=32 was reported inHypericum hircinum subsp.cambessedesii. It is suggested that the previous count (2n=40) could be explained by the presence of a…
Molecular diversity at the self-incompatibility locus is a salient feature in natural populations of wild tomato (Lycopersicon peruvianum)
1993
A cDNA encoding a stylar protein was cloned from flowers of self-incompatible wild tomato (Lycopersicon peruvianum). The corresponding gene was mapped to the S locus, which is responsible for self-incompatibility. The nucleotide sequence was determined for this allele, and compared to other S-related sequences in the Solanaceae. The S allele was used to probe DNA from 92 plants comprising 10 natural populations of Lycopersicon peruvianum. Hybridization was conducted under moderate and permissive stringencies in order to detect homologous sequences. Few alleles were detected, even under permissive conditions, underscoring the great sequence diversity at this locus. Those alleles that were de…
Divergent Evolution of an "Orphon" Historic Gene Cluster in Chironomus
1993
The histone genes of the midge Chironomus thummi thummi are organized in tandemly repeated gene groups, each containing the four core histone genes plus an H1 gene. These repetitive gene groups are found at five different loci, linked on one chromosomal arm. In addition to the clustered gene groups an isolated histone gene group exists which is found spatially separated on a different chromosome ("orphon" gene group). These orphon genes have been cloned and analysed in detail. Nucleotide sequence and in situ hybridization data suggest that the orphon gene group was established early during chironomid speciation, possibly by a transposition-like mechanism. This allowed the genes to be moved …
Karyotypic diversity among Blastocystis hominis isolates
1997
Fifteen Blastocystis hominis strains, 13 axenic and 2 monoxenic, have been included in the present study. The chromosomal pattern was analyzed by the contour-clamped homogeneous electric-field (CHEF) system. The number of chromosomes detected ranged between 9 and 13, with sizes from 2200 kbp to 260 kbp. Eleven karyotypic profiles, with a common pattern constituted by 8 chromosomes of 2200, 1280, 890, 840, 700, 650, 540 and 260 kbp, were observed. The Jaccard index demonstrated that the similarity between isolates ranged from 0.5714 to 1. The different isolates were clustered in 3 karyotypes (A: 8 isolates; B: 6 isolates and C: 1 isolate). All isolates grouped in karyotype A presented a char…
Karyotypes, Banding Patterns and Nuclear DNA Content inCrepidula unguiformisLamarck, 1822, andNaticarius stercusmuscarum(Gmelin, 1791) (Mollusca, Cae…
2009
ABSTRACT The chromosome complement and the nuclear DNA content in two caenogastropod species from the Mediterranean Sea, Crepidula unguiformis (Calyptraeidae) and Naticarius stercusmuscarum (Naticidae), were investigated by the application of both classical and molecular cytogenetic methods. Despite the constancy of haploid chromosome numbers (n = 17 in both species), C. unguiformis and N. stercusmuscarum show genome sizes amounting to 6.36 and 2.63 pg, respectively. Moreover, while N. stercusmuscarum resembles cytogenetically the other neotaenioglossan caenogastropods studied so far, C. unguiformis differs in: (i) number and location of rDNA clusters (ii), composition of telomeric repeats,…
FISH mapping of 18S-28S and 5S ribosomal DNA, (GATA)n and (TTAGGG)n telomeric repeats in the periwinkle Melarhaphe neritoides (Prosobranchia, Gastrop…
2001
Spermatocyte chromosomes of Melarhaphe neritoides (Mollusca, Prosobranchia, Caenogastropoda) were studied using fluorescent in situ hybridization (FISH) with four repetitive DNA probes (18S rDNA, 5S rDNA, (TTAGGG)n and (GATA)n). Single-colour FISH consistently mapped one chromosome pair per spread using either 18S or 5S rDNA as probes. The telomeric sequence (TTAGGG)n hybridized with termini of all chromosomes whereas the (GATA)n probe did not label any areas. Simultaneous 18S-5S rDNA and 18S-(TTAGGG)n FISH demonstrated that repeated units of the three multicopy families are closely associated on the same chromosome pair.
Loss of 1p in recurrent meningiomas
2001
Deletion of 1p is associated with histological progression to meningiomas. Detection of this alteration may be a predicting factor for recurrences in this tumor. We present 8 meningiomas from four patients: the original tumor and the first recurrence in one patient, and the first and second recurrences in the other three were studied. We compared results of monosomy 22 and deletion of chromosome 1p with cytogenetic methods and fluorescence in situ hybridization (FISH) analysis obtained from slides of direct preparations, of cultured cells and slides of touch preparations. The cytogenetic study showed normal chromosome 22 and deletion on 1p32 in both samples of one patient; only monosomy 22 …
Interphase FISH assays for the detection of translocations with breakpoints in immunoglobulin light chain loci
2002
Many B-cell malignancies bear chromosomal translocations juxtaposing immunoglobulin (IG) genes with oncogenes, resulting in deregulated expression of the latter. Translocations affecting the IG heavy chain (IGH) locus in chromosomal region 14q32 are most prevalent. However, variant translocations involving the IG kappa (IGK) locus in 2p12 or the IG lambda (IGL) locus in 22q11 occur recurrently in B-cell neoplasias. No routine methods for the detection of all breakpoints involving IG light chain loci independently of the translocation partner have been described. For this reason, we have designed 2 novel interphase fluorescence in situ hybridization (FISH) assays using differentially labeled…
Genetics of Polyglandular Failure
2016
The rare autoimmune polyglandular failure syndromes (APS) comprise a juvenile (APS1) and an adult type (APS2 and 3). APS1 is caused by mutations in the autoimmune regulatory (AIRE) gene on chromosome 21 and is inherited in an autosomal recessive manner. Mutations in the AIRE gene impair self-tolerance and result in defect proteins causing autoimmune destruction of target organs. Genetic testing identifies patients with APS1. For APS2/3 disease susceptibility genes are the human leucocyte antigen on chromosome 6, the cytotoxic T lymphocyte antigen (chromosome 2), the protein tyrosine phosphatase nonreceptor type 22 (chromosome 1), the forkhead box P3 (X chromosome), and the interleukin-2 rec…