Biomedical subjects

J M Quattro

Publications and source records attributed to J M Quattro.

26 records · Page 2Linked to original sources

PubMed1996

Ontogeny of odorant receptor gene expression in zebrafish, Danio rerio.

We cloned three putative odorant receptor (OR) genes from the zebrafish to use as in situ hybridization probes to follow the temporal patterns of neurons expressing OR genes through a developmental progression from embryo (12 h postfertilization) to adult. The identification of these genes is supported by sequence homology to previously reported ORs and by the morphology and location of labeled cells in in situ hybridization experiments. Cells expressing OR mRNA were first observed in the olfactory placodes between 31 and 38 h after fertilization (fish reared at 26 degrees C). Initially, only single cells were observed to hybridize the probe; the number of labeled cells increased throughout the remainder of embryogenesis and through postembryonic growth and morphogenesis of the olfactory organ. At all ages, the positively hybridizing cells were scattered throughout the olfactory epithelium but not in the nonsensory epithelium of the olfactory organ.

Amino Acid Sequence↗

PubMed1995

Evolutionary relations among vertebrate muscle-type lactate dehydrogenases.

Gene duplication has produced two lactate dehydrogenase (LDH) isozymes, LDH-A and LDH-B, that are found in essentially all vertebrates. On the basis of the biochemical properties of the LDH-A and LDH-B isozymes, it has been suggested that each locus is orthologous among all vertebrates. However, phylogenetic studies have not supported a common evolutionary history among the LDH-A isozymes, particularly when those from lower vertebrates are examined. We present here the sequence of a muscle-type LDH from Fundulus heteroclitus, a teleost fish for which the LDH-B sequence has been determined and shown to be unrelated phylogenetically to tetrapod LDH-A isozymes. Although the sequence of the teleost muscle LDH shares certain features with the LDH-A of tetrapods, phylogenetic analyses do not support an orthologous relation among the LDH-A isozymes of teleost fish and tetrapod vertebrates.

Amino Acid Sequence↗

PubMed1993

Sequence analysis of teleost retina-specific lactate dehydrogenase C: evolutionary implications for the vertebrate lactate dehydrogenase gene family.

At least two gene duplication events have led to the three lactate dehydrogenase (LDH; EC 1.1.1.27) isozymes (LDH-A, LDH-B, and LDH-C) of chordates. The prevailing model for the evolution of the LDH loci involves duplication of a primordial LDH locus near the origin of vertebrates, giving rise to Ldh-A and Ldh-B. A third locus, designated Ldh-C, is expressed in the spermatocytes of mammals and a single family of birds and in the eye or liver tissues of teleost fishes. Ldh-C might have arisen independently in these taxa as duplications of either Ldh-A or Ldh-B. Several authors have challenged this traditional hypothesis on the basis of amino acid sequence and immunological similarity of the three LDH isozymes. They suggest that the primordial LDH gene was duplicated to form Ldh-C and a locus that later gave rise to Ldh-A and Ldh-B. We have differentiated between these hypotheses by determining the cDNA sequence of the retina-specific LDH-C from a teleost, Fundulus heteroclitus. On the basis of amino acid sequence similarity, we conclude that the LDH-C isozymes in fish and mammals are not orthologous but derive from independent gene duplications. Furthermore, our phylogenetic analyses support previous hypotheses that teleost Ldh-C is derived from a duplication of the Ldh-B locus.

Amino Acid Sequence↗

PubMed1992

An ancient clonal lineage in the fish genus Poeciliopsis (Atheriniformes: Poeciliidae).

Genetic diversity in mtDNA was assessed within the unisexual (all female) hybridogenetic fish Poeciliopsis monacha-occidentalis and the two sexual species from which it arose. Results confirm that P. monacha was the maternal ancestor and that paternal leakage of P. occidentalis mtDNA has not occurred. Of particular interest is the high level of de novo mutational divergence within one hybridogenetic lineage that on the basis of independent zoogeographic considerations, protein electrophoretic data, and tissue grafting analysis is of monophyletic (single hybridization) origin. Using a conventional mtDNA clock calibration, we estimate that this unisexual clade might be >100,000 generations old. Contrary to conventional belief, this result shows that some unisexual vertebrate lineages can achieve a substantial evolutionary age.

Journal Article↗

PubMed1992

Mode of origin and sources of genotypic diversity in triploid gynogenetic fish clones (Poeciliopsis: Poeciliidae).

Most tributaries of the Río Fuerte in northwestern Mexico contain one or more clones of allotriploid fish of the genus Poeciliopsis. We used multilocus allozyme genotypes and mitochondrial DNA (mtDNA) haplotypes to examine several potential modes of origin of these gynogenetic all-female fish. The allozyme studies corroborated earlier morphological work revealing the hybrid constitution of two triploid biotypes, Poeciliopsis 2 monacha-lucida and Poeciliopsis monacha-2 lucida. Each biotype carries one or two whole genomes from the each of the sexual species P. monacha and P. lucida. Restriction site analysis of mtDNA revealed that P. monacha was the maternal ancestor of five electrophoretically distinguishable triploid clones. Four of five clones were marked by closely related, composite, allozyme/mtDNA genotypes, suggesting they had common origins from an allodiploid clone of the P. monacha-lucida biotype. Genotypic analysis revealed that all five clones arose via the "genome addition" pathway. Fertilization of unreduced ova in P. monacha-lucida females by sperm from P. monacha and P. lucida males, respectively, gave rise to both biotypes.

Animals↗

PubMed1992

Analysis of molecular variance inferred from metric distances among DNA haplotypes: application to human mitochondrial DNA restriction data.

We present here a framework for the study of molecular variation within a single species. Information on DNA haplotype divergence is incorporated into an analysis of variance format, derived from a matrix of squared-distances among all pairs of haplotypes. This analysis of molecular variance (AMOVA) produces estimates of variance components and F-statistic analogs, designated here as phi-statistics, reflecting the correlation of haplotypic diversity at different levels of hierarchical subdivision. The method is flexible enough to accommodate several alternative input matrices, corresponding to different types of molecular data, as well as different types of evolutionary assumptions, without modifying the basic structure of the analysis. The significance of the variance components and phi-statistics is tested using a permutational approach, eliminating the normality assumption that is conventional for analysis of variance but inappropriate for molecular data. Application of AMOVA to human mitochondrial DNA haplotype data shows that population subdivisions are better resolved when some measure of molecular differences among haplotypes is introduced into the analysis. At the intraspecific level, however, the additional information provided by knowing the exact phylogenetic relations among haplotypes or by a nonlinear translation of restriction-site change into nucleotide diversity does not significantly modify the inferred population genetic structure. Monte Carlo studies show that site sampling does not fundamentally affect the significance of the molecular variance components. The AMOVA treatment is easily extended in several different directions and it constitutes a coherent and flexible framework for the statistical analysis of molecular data.

Analysis of Variance↗

PubMed1991

Molecular evidence for multiple origins of hybridogenetic fish clones (Poeciliidae:Poeciliopsis).

Hybrid matings between the sexual species Poeciliopsis monacha and Poeciliopsis lucida produced a series of diploid all-female lineages of P. monacha-lucida that inhabit the Río Fuerte of northwestern Mexico. Restriction site analyses of mitochondrial DNA (mtDNA) clearly revealed that P. monacha was the maternal ancestor of these hybrids. The high level of mtDNA diversity in P. monacha was mirrored by similarly high levels in P. monacha-lucida; thus hybridizations giving rise to unisexual lineages have occurred many times. However, mtDNA variability among P. monacha-lucida lineages revealed a geographical component. Apparently the opportunity for the establishment of unisexual lineages varies among tributaries of the Río Fuerte. We hypothesize that a dynamic complex of sexual and clonal fishes appear to participate in a feedback process that maintains genetic diversity in both the sexual and asexual components.

Animals↗

PubMed1989

Fitness differences among remnant populations of the endangered sonoran topminnow.

Four correlates of fitness were measured in three stocks of the endangered Sonoran topminnow, Poeciliopsis occidentalis, from Arizona. Survival, growth, early fecundity, and developmental stability were greatest in laboratory-reared fish from the most heterozygous natural population studied. Conversely, all four traits were poorest in fish from a population with no electrophoretically detectable genetic variation. These results emphasize the need for genetic as well as demographic information for the development of comprehensive species recovery programs.

Animals↗