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Biomedical subjects

J L Doyle

Publications and source records attributed to J L Doyle.

At least 19 recordsLinked to original sources
PubMed2000

Divergent human and mouse orthologs of a novel gene (WBSCR15/Wbscr15) reside within the genomic interval commonly deleted in Williams syndrome.

Williams syndrome (WS) is a contiguous gene deletion disorder resulting in complex and intriguing clinical features. Detailed molecular characterization studies of the genomic segment on human chromosome 7q11.23 commonly deleted in WS have uncovered numerous genes, each of which is being actively studied for its possible role in the etiology of the syndrome. Our efforts have focused on the comparative mapping and sequencing of the WS region in human and mouse. In previous studies, we uncovered important differences in the long-range organization of these human and mouse genomic regions; in particular, the notable absence of large duplicated blocks of DNA in mouse that are present in human. Aided by available genomic sequence data, we have used a combination of gene-prediction programs and cDNA isolation to identify the human and mouse orthologs of a novel gene (WBSCR15 and Wbscr15, respectively) residing within the genomic segment commonly deleted in WS. Unlike the flanking genes, which are closely related in human and mouse, WBSCR15 and Wbscr15 are strikingly different with respect to their cDNA and corresponding protein sequences as well as tissue-expression pattern. Neither the WBSCR15- nor Wbscr15-encoded amino acid sequence shows a statistically significant similarity to any characterized protein. These findings reveal another interesting evolutionary difference between the human and mouse WS regions and provide an additional candidate gene to evaluate with respect to its possible role in the pathogenesis of WS.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Intracellular gene transfer in action: dual transcription and multiple silencings of nuclear and mitochondrial cox2 genes in legumes.

The respiratory gene cox2, normally present in the mitochondrion, was previously shown to have been functionally transferred to the nucleus during flowering plant evolution, possibly during the diversification of legumes. To search for novel intermediate stages in the process of intracellular gene transfer and to assess the evolutionary timing and frequency of cox2 transfer, activation, and inactivation, we examined nuclear and mitochondrial (mt) cox2 presence and expression in over 25 legume genera and mt cox2 presence in 392 genera. Transfer and activation of cox2 appear to have occurred during recent legume evolution, more recently than previously inferred. Many intermediate stages of the gene transfer process are represented by cox2 genes in the studied legumes. Nine legumes contain intact copies of both nuclear and mt cox2, although transcripts could not be detected for some of these genes. Both cox2 genes are transcribed in seven legumes that are phylogenetically interspersed with species displaying only nuclear or mt cox2 expression. Inactivation of cox2 in each genome has taken place multiple times and in a variety of ways, including loss of detectable transcripts or transcript editing and partial to complete gene loss. Phylogenetic evidence shows about the same number (3-5) of separate inactivations of nuclear and mt cox2, suggesting that there is no selective advantage for a mt vs. nuclear location of cox2 in plants. The current distribution of cox2 presence and expression between the nucleus and mitochondrion in the studied legumes is probably the result of chance mutations silencing either cox2 gene.

Cell Nucleus↗
PubMed1999

Origins, colonization, and lineage recombination in a widespread perennial soybean polyploid complex.

Polyploidy is a dominant feature of flowering plant genomes, including those of many important crop species, implying that polyploidy confers evolutionary advantages on plant species. Recent molecular studies suggest that polyploids often originate many times from the same progenitor diploids. For this to provide a broader genetic base for a polyploid species, there must be lineage recombination in the genomes of polyploids having different origins, and this has rarely been documented in recently formed wild polyploid species. Glycine tabacina, a wild relative of soybean, forms a widespread polyploid complex in Australia and the islands of the Pacific Ocean. In a sample of 40 G. tabacina plants, DNA sequence variation at one homoeologous histone H3-D locus identified three alleles, each also found in Australian diploid Glycine species. These data agree with our previous studies of chloroplast DNA variation in suggesting that this polyploid has originated several times. Both the origins of the polyploid and several independent dispersals from Australia to oceanic islands appear to have occurred within the last 30,000 years. The distributions of histone alleles, chloroplast haplotypes, and alleles at two isozyme loci were uncorrelated, and 20 multilocus genotypes were found among the 40 plants sampled. Extensive lineage recombination is thus hypothesized in the polyploid, involving migration and occasional outcrossing in this predominantly inbreeding species. The combination of multiple origins with gene exchange among lineages increases the genetic base of a polyploid and may help explain the wide colonization of polyploid G. tabacina relative to its diploid progenitors.

Journal Article↗
PubMed1999

Malignant spindle cell tumor arising in the mandible of a patient with florid osseous dysplasia.

Florid osseous dysplasia is a non-neoplastic condition of the alveolar processes of the jaws characterized by the replacement of multiple foci of bone by fibrous connective tissue, accompanied by gradual deposition of cementum, bone, or both. The lesions are not associated with inflammatory diseases of the dental pulp or periodontal tissues. In fully developed florid osseous dysplasia, there are multiple lobulated masses in the alveolar bone bilaterally in the mandible and sometimes in the maxilla. This is the first report of a malignancy originating within the jaws of a patient with florid osseous dysplasia. A spindle cell malignancy was diagnosed in the mandible of a 54-year-old black woman whose jaw was affected by florid osseous dysplasia bilaterally. Despite extensive surgery and radiotherapy, the patient died 20 months after diagnosis of the malignancy.

Fatal Outcome↗
PubMed1999

Incongruence in the diploid B-genome species complex of Glycine (Leguminosae) revisited: histone H3-D alleles versus chloroplast haplotypes.

Variation at the single-copy nuclear locus histone H3-D was surveyed in the diploid B-genome group of Glycine subgenus Glycine (Leguminosae: Papilionoideae), which comprises three named Australian species and a number of distinct but as yet not formally recognized taxa. A total of 23 alleles was identified in the 44 accessions surveyed. Only one individual was clearly heterozygous, which is not surprising given the largely autogamous breeding system of subgenus Glycine. Alleles differed by as many as 19 nucleotide substitutions, nearly all in the three introns; length variation was minimal. Phylogenetic analysis identified two shortest allele trees with very little homoplasy, suggesting that recombination has been rare. Both topological and data set incongruence were statistically significant between histone H3-D allele trees and trees inferred from chloroplast DNA haplotypes previously described from these same accessions. Whereas the distribution of H3-D alleles agrees well with morphologically based taxonomic groupings, chloroplast DNA haplotype polymorphisms transgress species boundaries, suggesting that the chloroplast genome is not tracking taxic relationships. Divergences among chloroplast DNA haplotypes involved in such transgressive patterns appear to be more recent than speciation events, suggesting hybridization rather than lineage sorting.

Alleles↗
PubMed1998

Ataxia, arrhythmia and ion-channel gene defects.

Ion channels are essential to a wide range of physiological functions including neuronal signaling, muscle contraction, cardiac pacemaking, hormone secretion and cell proliferation. The important role that highly regulated ion influx plays in these processes has been underscored by a recent flurry of discoveries linking ion-channel gene mutations to inherited disorders. Ion channels of many different types have been demonstrated as being causative factors in genetic disease. This review discusses the growing number of disorders associated with genes of the voltage-gated ion channel superfamily, with special focus on those characterized by neurological, neuromuscular, or cardiac dysfunction in humans and mice.

Animals↗
PubMed1996

The distribution and phylogenetic significance of a 50-kb chloroplast DNA inversion in the flowering plant family Leguminosae.

Species in 9 of the approximately 650 genera of the flowering plant family Leguminosae are known to possess a large (50-kb) inversion in their chloroplast genomes, relative to the gene order found most commonly among land plants. Putatively basal elements of the family have not been surveyed for the inversion, which is unknown outside the legumes. Using a combination of polymerase chain reaction and restriction-mapping approaches employing primers or hybridization probes flanking inversion endpoints, 132 legume genera were screened for the presence of the inversion. The inversion was found to be absent in all taxa from two of the three subfamilies (Mimosoideae and Caesalpinioideae), whereas the inversion was found to be present in most taxa of the third subfamily (Papilionoideae). Two papilionoid tribes, Swartzieae and Sophoreae, were heterogeneous for the inversion, which is consistent with a number of lines of evidence suggesting the polyphyly of these tribes. The 50-kb inversion appears to be a unique event in the evolution of Leguminosae, providing a synapomorphy for a clade that includes most of the Papilionoideae.

Base Sequence↗
PubMed1996

Genetic analysis of Netrin genes in Drosophila: Netrins guide CNS commissural axons and peripheral motor axons.

Two tandem Netrin genes in Drosophila are expressed at the midline of the developing CNS and in different subsets of neurons, muscles, and epidermal patches. In embryos carrying a small deficiency that deletes both genes, CNS axon commissures are partially missing or thinner. This phenotype is rescued by expressing either Netrin gene at the midline. Pan-neural expression of either gene causes disruption of commissural and longitudinal tracts, indicating that the pattern of Netrin expression is crucial and that Netrins function as instructive cues. The double mutant also shows defects in motor axon projections. Expression of either Netrin gene in all muscles also results in aberrant motor projections. Thus, Drosophila Netrins are required for the guidance of commissural axons at the midline, and of motor axons to their target muscles.

Animals↗
PubMed1994

Leiomyoma of the oral cavity: a light microscopic and immunohistochemical study with review of the literature from 1884 to 1992.

Leiomyoma is the most common benign neoplasm in the uterus and stomach but is rare in the oral cavity. There were only 5 oral cases in a series of 7748 leiomyomas of all sites. Benign smooth muscle neoplasms are classified into leiomyoma (solid leiomyoma), angiomyoma (vascular leiomyoma) and epithelioid leiomyoma (leiomyoblastoma). 6 cases diagnosed as leiomyoma were retrieved from the files of two oral biopsy services over the past 25 years. A light microscopic study including trichrome and phosphotungstic acid haematoxylin (PTAH) stains, and an immunohistochemical study with the following markers: desmin, muscle specific actin, myoglobin, vimentin, S-100 protein, neuron-specific enolase, factor VIII and Ulex europeus were done with suitable controls. The haematoxylin and eosin and Masson's trichrome stains supported a diagnosis of leiomyoma in all 6 cases but PTAH was positive in only 3 of them. The immunohistochemical study confirmed the diagnosis of leiomyoma in 3 cases. The other 3 were identified as granular cell tumour, myofibroma and neurofibroma, respectively. The review of the literature contributed the following data: mean age was 41 and median age 39 in 134/142 patients. A male sex prevalence 72/137 patients (54.0%) was noted. The lips were the most common site with 39 cases (27.46%) followed by the tongue 26 (18.30%), cheeks and palate 22 (15.49%), gingiva 12 (8.45%), and mandible 8 (5.63%). Prognosis of oral leiomyomas is excellent. Immunohistochemistry is a precise and reliable method for definitive diagnosis of oral leiomyoma.

Adolescent↗
PubMed1993

Malignant transformation of peripheral ameloblastoma.

A peripheral (extraosseous) ameloblastoma was excised from the maxillary left tuberosity of an 82-year-old man. It recurred twice over a 5-year period, once as squamous cell carcinoma and again as undifferentiated carcinoma. Analysis of the literature suggests that peripheral ameloblastomas may have the same potential for malignant transformation as intraosseous ameloblastomas.

Aged↗
PubMed1993

Clear cell odontogenic carcinoma with lymph node metastasis.

Clear cell odontogenic tumors are rare. Review of the literature showed 9 cases with a prominent clear cell component. These lesions have exhibited an aggressive behavior characterized by an infiltrative local growth pattern, recurrence, or metastases. We report a case of an odontogenic tumor that exhibited a biphasic pattern and was characterized by lymph node involvement identical histologically to the primary tumor. We conclude that the presence of a clear cell component in an ameloblastomatous tumor should be viewed as a sign of de-differentiation, and that a malignancy with or without metastases should be considered and ruled out in such cases.

Adenocarcinoma↗
PubMed1990

Multiple origins of polyploids in the Glycine tabacina complex inferred from chloroplast DNA polymorphism.

The Glycine tabacina polyploid complex has been shown to include a minimum of two morphological and crossing groups, which also differ in chloroplast DNA (cpDNA) restriction map and nuclear ribosomal gene repeat phenotype. These AAB2B2 and BBB2B2 G. tabacina polyploids contain plastomes referable to the A and B diploid plastome groups of subgenus Glycine, respectively. Eight different cpDNA variants were observed among the 65 B-type polyploids studied, six of which were identical for numerous restriction site characters to plastome types found among the highly polymorphic B genome diploid species. It is hypothesized that there have been numerous independent origins of polyploid G. tabacina: at least one AA x B2B2 event and a minimum of five BB x B2B2 events involving different BB types as female progenitor. Low amounts of cpDNA divergence between diploid and polyploid plastomes and among the plastomes of geographically disjunct polyploids suggest that the origin and dispersal of polyploids are relatively recent events. All hypothesized diploid progenitors are native to Australia, while both A- and B-type G. tabacina polyploids occur on islands of the Pacific outside the range of diploids. The presence of several different plastome types of polyploid G. tabacina in the Pacific islands suggests that several colonization events have occurred.

Journal Article↗