Walking, cloning, and mapping with yeast artificial chromosomes: a contig encompassing D21S13 and D21S16.

Chromosome 21 has often been used as a model system for the development of genome mapping and cloning strategies in humans. In this report methods for systematic chromosome walking, cloning, and mapping are exemplified in the construction of a 1.5-Mb yeast artificial chromosome (YAC) contig encompassing and extending 400 kb beyond each of the genetic loci D21S13 and D21S16.

Segregation of structural collagen genes in adolescent idiopathic scoliosis.

The etiology of idiopathic scoliosis remains unknown. The condition results in a characteristic deformity of the spine and surrounding tissues. Both Types I and II collagen are important constituents of the affected tissues, and thus defective collagens are reasonable candidates for the primary abnormality in adolescent idiopathic scoliosis (AIS).

A limited association of generalized osteoarthritis with alleles at the type II collagen locus: COL2A1.

A significant genetic influence in osteoarthritis has been observed in the combination of Heberden's nodes and generalized osteoarthritis. We examined whether mutation in the gene encoding the major cartilage matrix protein type II collagen was responsible by comparing allele frequencies at the locus (COL2A1) in a group of 61 patients with nodal GOA with a control population and by analysing the COL2A1 genotypes of 21 affected sibling pairs. There were no significant allele differences but a slightly increased tendency over chance alone for affected siblings to have inherited the same COL2A1 alleles from their parents.

Segregation analysis of the structural genes of the major fibrillar collagens provides further evidence of molecular heterogeneity in type II Ehlers-Danlos syndrome.

Type II Ehlers-Danlos syndrome (EDS) is one of a group of disorders characterized by striking abnormalities of the soft connective tissues. The major fibrillar collagens (types I and III) found in these tissues have important stress-bearing functions and abnormal collagen could therefore account for the clinical features of this condition. We have used a number of restriction site dimorphisms, tightly linked to the structural genes of type I collagen (COL1A1 COL1A2) and type III collagen (COL3A1), to investigate the segregation of corresponding alleles in three pedigrees in which type II EDS was clearly inherited as a dominant trait.

Genetic analysis in cystic fibrosis using the amplification refractory mutation system (ARMS): the J3.11 MspI polymorphism.

A new method of genetic analysis has been devised. The method, amplification refractory mutation system (ARMS), has been used to genotype the J3.11 MspI restriction fragment length polymorphism (RFLP) closely linked to cystic fibrosis (CF).

Prenatal diagnosis of osteogenesis imperfecta by identification of the concordant collagen 1 allele.

Dominantly inherited osteogenesis imperfecta is consistently linked to the two loci encoding the alpha 1 and alpha 2 subunits of collagen 1, the predominant bone collagen. We have performed several prenatal diagnoses based on identification of the segregating allele at the concordant locus in chorionic villus samples both in families where the linkage can be independently shown and in those where it cannot. Especially in the latter category, calculation of the final risk must incorporate an estimate of genetic heterogeneity within the OI population to give a prior probability of linkage.

A yeast artificial chromosome contig encompassing the cystic fibrosis locus.

The gene responsible for cystic fibrosis (CF) has recently been identified. Coding sequence for the cystic fibrosis transmembrane conductance regulator (CFTR) spans at least 230 kb of the human genome. Although all 27 exons of the gene are represented in cosmid or bacteriophage clones, there are still several gaps in the physical map of this region.

A novel, rapid method for the isolation of terminal sequences from yeast artificial chromosome (YAC) clones.

The recent development of yeast artificial chromosome (YAC) vectors has provided a system for cloning fragments that are over ten times larger than those that can be cloned in more established systems. We have developed a method for the rapid isolation of terminal sequences from YAC clones. The YAC clone is digested with a range of restriction enzymes, a common linker is ligated to the DNA fragments and terminal sequences are amplified using a vector specific primer and a linker specific primer.

Consistent linkage of dominantly inherited osteogenesis imperfecta to the type I collagen loci: COL1A1 and COL1A2.

The segregation of COL1A1 and COL1A2, the two genes which encode the chains of type I collagen, was analyzed in 38 dominant osteogenesis imperfecta (OI) pedigrees by using polymorphic markers within or close to the genes. This was done in order to estimate the consistency of linkage of OI genes to these two loci. None of the 38 pedigrees showed evidence of recombination between the OI gene and both collagen loci, suggesting that the frequency of unlinked loci in the population must be low.

Ultrastructural features of degeneration of the gallbladder during lamprey biliary atresia.

Thin sections and freeze-fracture replicas were used to examine the fine structural features of degeneration of the gallbladder during lamprey biliary atresia. The cells of the epithelium undergo a progressive accumulation of dense bodies and vacuoles, loss of glycogen, condensation of the filamentous ectoplasm, fragmentation of microvilli, and dilation of cisternae of rough endoplasmic reticulum but eventually disappear by stage 4 of metamorphosis. Zonulae occludentes in the epithelium show a progressive increase in apical-basal depth as the junctional strands fragment.

Intercellular junctions during development of the definitive kidney in lampreys: freeze fracture and morphometric analyses.

The changing morphology of intercellular junctions in renal morphogenesis during lamprey metamorphosis was followed using freeze-fracture replicas and morphometry. Gap junctions and particle aggregates among strands of occluding junctions are conspicuous in the differentiating podocytes of the renal corpuscle and in the early ciliated neck and proximal segments but not in the distal segment. The cells of the segmented nephron arise from alpha nephrogenic cells which have a focal aggregate (macula occludens) of 4.

Genetic segregation analysis of familial mitral valve prolapse shows no linkage to fibrillar collagen genes.

Three pedigrees were identified in which mitral valve prolapse seemed to be inherited as a mendelian autosomal dominant trait. The segregation of the genes encoding the major fibrillar collagens present in valve tissue, collagens I and III, was analysed by use of restriction enzyme site variants as genetic markers. In one pedigree there was discordance between the segregation of the disease and markers for all three collagen genes.

Structural and segregation analysis of the type II collagen gene (COL2A1) in some heritable chondrodysplasias.

Seventy-seven persons with a variety of heritable chondrodysplasias were screened for gross rearrangements of the structural gene encoding the major cartilage collagen, collagen II. None was found. Segregation of the locus (COL2A1) was studied in 19 pedigrees using three restriction site dimorphisms (shown by PvuII, HindIII, and BamHI) and a length polymorphism as linkage markers.

Homozygous osteogenesis imperfecta unlinked to collagen I genes.

In a consanguineous pedigree in which a severe type of osteogenesis imperfecta was segregating as an autosomal recessive trait, analysis of genetic markers for both collagen I structural loci COL1A1 and COL1A2 showed that the phenotype was unlinked to either locus.

Segregation of all four major fibrillar collagen genes in the Marfan syndrome.

Linkage markers at or close to the genes encoding the three major fibrillar collagens were used to analyze the segregation of these loci in six pedigrees with dominantly inherited Marfan syndrome. Four pedigrees were discordant at one of the Type I collagen loci (COL1A2), and, of these, two were discordant at the other Type I locus (COL1A1). The Marfan syndrome also segregated independently of the structural loci for Type II and Type III collagen in these two families.

Life satisfaction and identity structure in late middle-aged men and women.

A total of 32 retirement-age subjects (17 men and 15 women) provided information about their lives by rating each of their identities in terms of a list of self-generated features. They also rank-ordered their currently enacted identities in terms of time spent in each and completed a life-satisfaction questionnaire. The Identities X Features matrices were analyzed by algorithms that generated a hierarchical model of identity structure for each subject based on feature ratings.

Nonparenchymal liver cells and granulomas during lamprey biliary atresia.

Transmission (thin sections and freeze-fracture replicas) and scanning electron microscopy were used to describe the nonparenchymal liver cells during the seven (1-7) stages of metamorphosis in the sea lamprey, Petromyzon marinus L., when bile ducts and canaliculi degenerate. The biliary atresia is accompanied by an increased diameter of fenestrae in the endothelium, an active phagocytosis by Kupffer cells in the sinusoids, and large lipid inclusions in perisinusoidal lipocytes (fat-storing or Ito cells).

Joint mobility with particular reference to racial variation and inherited connective tissue disorders.

Joint mobility scores were compared in 248 normal English Caucasian males and females between the ages of 8 and 70 years. The results were contrasted with those in a group of normal Asian Indians and patients suffering from a variety of inherited disorders including Type II Ehlers-Danlos syndrome (EDS), Type I osteogenesis imperfecta (OI), Marfan syndrome, generalized osteoarthritis (GOA), achondroplasia and pseudoachondroplasia. The first-degree relatives of ten subjects with severe or lethal OI were also examined.

Gap junctions and zonulae occludentes of hepatocytes during biliary atresia in the lamprey.

Gap junctions and zonulae occludentes of hepatocytes were examined in thin sections and freeze-fracture replicas from livers of larval and juvenile adult lampreys and during the phase of metamorphosis when bile ducts and bile canaliculi disappear (biliary atresia). Larvae possess zonulae occludentes at the canaliculi which are composed of one to five (mean = 2.81) junctional strands that provide a bile-blood barrier.

Osteogenesis imperfecta is linked to both type I collagen structural genes.

The segregation of the two type I collagen structural gene loci COL1A1 and COL1A2 was analysed in eleven osteogenesis imperfecta pedigrees by means of restriction-site variants at, or close to, these loci. In each case, the OI gene was inherited with one or other collagen locus. As well as identifying the common OI loci the result of this analysis sets limits on the frequency of a third locus and lays the foundation for a widely available antenatal diagnostic test.

Morphology of the green livers in upstream migrants of Petromyzon marinus L.

A morphological comparison was made of the green livers of male and female lampreys (Petromyzon marinus L.) collected during the upstream (prespawning) migration. Light and electron microscope histochemistry for iron, and both thin sections and freeze-fracture replicas in the electron microscope, revealed some sexual dimorphism in these livers.