Microsatellite genotyping of Chromosome 14q13.2-14q13 in the vicinity of proteasomal gene<Emphasis Type="Italic"> PSMA6</Emphasis> and association with Graves’ disease in the Latvian population

The 270-kb Chromosome 14q13.2-14q13 region harboring the proteasomal alpha subunit 6 gene PSMA6 was analyzed for polymorphism of five microsatellite repeats in cases/controls and association with Graves disease. Four novel microsatellite markers were localized to the 14q13.2 region upstream of PSMA6. Dinucleotide repeats HSMS801, HSMS702, HSMS701 were identified in two introns of the gene KIAA0391; the most upstream trinucleotide HSMS602 marker was found in an intron of the C14orf24 gene. A polymorphism study performed on the Latvian population revealed 13 and 14 alleles for HSMS801 and HSMS702, respectively, seven alleles for HSMS701, and four alleles for HSMS602. Heterozygosity analysis revealed that all the four markers obey Hardy-Weinberg distribution. The previously described HSMS006 marker, represented by 12 alleles, is localized in intron 6 of the PSMA6 gene. No significant differences were observed between patients and controls in allele distribution of the HSMS702 and HSMS701 microsatellite repeats. However, the allele frequencies of HSMS006 and HSMS801 were significantly different between Graves disease and control subjects. The 181- and 185-bp alleles of HSMS006 and the 133-, 143-, and 149-bp alleles of HSMS801 were found more often, but the 189- and 191-bp alleles of HSMS006 were much less frequent in Graves disease patients compared with the controls. An additional 174-bp allele of the HSMS602 marker, absent in healthy subjects, was found in Graves disease patients.     

Host controlled plasmid replication: Escherichia coli minichromosomes

Escherichia coli minichromosomes are plasmids replicating exclusively from a cloned copy of oriC, the chromosomal origin of replication. They are therefore subject to the same types of replication control as imposed on the chromosome. Unlike natural plasmid replicons, minichromosomes do not adjust their replication rate to the cellular copy number and they do not contain information for active partitioning at cell division. Analysis of mutant strains where minichromosomes cannot be established suggest that their mere existence is dependent on the factors that ensure timely once per cell cycle initiation of replication. These observations indicate that replication initiation in E. coli is normally controlled in such a way that all copies of oriC contained within the cell, chromosomal and minichromosomal, are initiated within a fairly short time interval of the cell cycle. Furthermore, both replication and segregation of the bacterial chromosome seem to be controlled by sequences outside the origin itself.     

Interstitial "de novo" tandem duplication of 7(q31.1-q35): first reported case

A patient carrying a de novo 7q31-35 duplication is presented. The tandem duplication was confirmed by FISH analysis. The case seems to be the first in the literature and, in spite of the large size of the duplicated region, he shows mild facial dysmorphism and a moderate mental retardation. The clinical findings of the dup7q published cases are compared in order to define a possible common phenotype.     

小叶锦鸡儿的核型分析

本文对小叶锦鸡儿进行细胞水平的核型分析,可得出结论：小叶锦鸡儿（Caragana microphylla Lam.)体细胞染色体数目为2n=16,其核型公式为2n=2x=14m(2SAT) 2M,桉stebbins的核型分析原则,小叶锦鸡儿的核型属1A型。     

Mitochondrial DNA mutations as a fundamental mechanism in physiological declines associated with aging

The hypothesis that mitochondrial DNA damage accumulates and contributes to aging was proposed decades ago. Only recently have technological advancements, which facilitate microanalysis of single cells or portions of cells, revealed that mtDNA deletion mutations and, perhaps, single nucleotide mutations accumulate to physiologically relevant levels in the tissues of various species with age. Although a link between single nucleotide mutations and physiological consequences in aging tissue has not been established, the accumulation of deletion mutations in skeletal muscle fibres has been associated with sarcopenia. Different, and apparently random, deletion mutations are specific to individual fibres. However, the mtDNA deletion mutation within a phenotypically abnormal region of a fibre is the same, suggesting a selection, amplification and clonal expansion of the initial deletion mutation. mtDNA deletion mutations within a muscle fibre are associated with specific electron transport system abnormalities, muscle fibre atrophy and fibre breakage. These data point to a causal relationship between mitochondrial DNA mutations and the age-related loss of muscle mass.     

Characterisation of Triticum vavilovii-derived stripe rust resistance using genetic,cytogenetic and molecular analyses and its marker-assisted selection

Stripe rust resistance was identified in Triticum vavilovii (T. vavilovii Aus22498)-derived Russian wheat aphid (RWA)-resistant germplasm. Inheritance studies indicated monogenic control of resistance. The resistance gene was tentatively designated as Yrvav and was located on chromosome 1B by monosomic analysis. A close association (1.5±0.9% recombination) of Yrvav with a T. vavilovii-derived gliadin allele (Gli-B1vav) placed it in chromosome arm 1BS. Yrvav was allelic with Yr10. Tests with Yr10 avirulent and virulent pathotypes showed that Yrvav and Yr10 possess identical pathogenic specificity. Yrvav and Yr10 showed close genetic associations with alternate alleles at the Xpsp3000 (microsatellite marker), Gli-B1 and Rg1 loci. Based on these observations Yrvav was named as Yr10vav. The close association between Xpsp3000 and Gli-B1 was also confirmed. The Yr10vav-linked Xpsp3000 allele (285 bp) was not present in 65 Australian cultivars, whereas seven Australian wheats lacking Yr10 carried the same Xpsp3000 allele (260 bp) as Yr10 carrying wheat cultivar Moro. Xpsp3000 and/or Gli-B1 could be used in marker-assisted selection for pyramiding Yr10vav or Yr10 with other stripe rust resistance genes. Yr10vav was inherited independently of the T. vavilovii-derived RWA resistance. Received: 5 December 2000 / Accepted: 3 April 2001     

Congenitally caused fused labia in the common marmoset (Callithrix jacchus)

In this paper, the occurrence of an external genital abnormality in female marmoset monkeys (fused labia) is discussed. This malformation was detected, for the first time, in a group of animals at the German Primate Center (GPC), Goettingen. The malformed vulva was completely sealed except for an opening of 1.5-2.5 mm around the urethra sufficient for urination. Because of this defect the animals were not able to copulate. As a consequence, the affected females were functionally infertile although they had a normal genital tract and a regular cycle. This vulvar abnormality was found in 12 females, offspring of 10 pairs in which either one or both came to the German Primate Center from two genetically related colonies in Munich, Germany, and one colony in Basel, Switzerland. The abnormality appeared to be recessive and inheritable from either parent. In pairs in which both animals were from one of the mentioned colonies, 45% of the female offspring were affected. In pairs where only one partner came from these colonies, 26% of female offspring had the malformation. These results indicate that avoidance of inbreeding, which is frequently performed in primate colonies, may reduce, but not eliminate the expression of abnormalities of genetic origin. Therefore selective breeding is required, and, in colonies where these recessive mutations are widespread, the development of genetic screening tests would be advantageous.