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At least 1,207 records · Page 67Linked to original sources
PubMed2000

Ancyromonadida: a new phylogenetic lineage among the protozoa closely related to the common ancestor of metazoans, fungi, and choanoflagellates (Opisthokonta).

Molecular and morphological evidence points to the ancyromonad Ancyromonas as a plausible candidate for the closest relative to the common ancestor of metazoans, fungi, and choanoflagellates (the Opisthokonta). Using 18S rDNA sequences from most of the major eukaryotic lineages, maximum-likelihood, minimum-evolution, and maximum-parsimony analyses yielded congruent phylogenies supporting this hypothesis. Combined with ultrastructural similarities between Ancyromonas and opisthokonts, the evidence presented here suggests that Ancyromonas may form an independent lineage, the Ancyromonadida Cavalier-Smith 1997, closer in its relationship to the opisthokonts than is its nearest protist relatives, the Apusomonadida. However, the very low bootstrap support for deep nodes and hypothesis testing indicate that the resolving power of 18S rDNA sequences is limited for examining this aspect of eukaryotic phylogeny. Alternate branching positions for the Ancyromonas lineage cannot be robustly rejected, revealing the importance of ultrastructure when examining the origins of multicellularity. The future use of a multigene approach may additionally be needed to resolve this aspect of eukaryotic phylogeny.

Animals↗
PubMed2000

Multiple lineages of the mitochondrial gene NADH dehydrogenase subunit 1 (ND1) in parasitic helminths: implications for molecular evolutionary studies of facultatively anaerobic eukaryotes.

The task of using partial ND1 sequences to infer a phylogeny for species of the genus Paragonimus (Trematoda: Digenea) was complicated by the discovery of at least two ND1 lineages within individual worms. The divergence of the ND1 lineages is shown by phylogenetic analysis not only to predate the divergence of the three Paragonimus species or species groups investigated but also the divergence of some trematode families. Some sequences are clearly pseudogenes as they contain single base deletions and/or premature termination codons. The presence of both pseudogenes and/or mitochondrial heteroplasmy are invoked to explain the presence of multiple and divergent ND1 lineages in these trematodes, which have two distinct cytochemical types of mitochondria. The implications for phylogenetic studies generally and of parasitic helminths specifically, using ND1 sequence data, are discussed. The ability of these organisms to adapt their metabolic processes to the variable availability of oxygen as an electron acceptor are proposed to explain some of the molecular diversity observed in parasitic helminths and possibly also in other anaerobically adapted eukaryotes.

Animals↗
PubMed1997

Cw*1701 defines a divergent african HLA-C allelic lineage.

The complete sequence of a new HLA-C allele, Cw*1701, was determined from a South African Zulu individual. Unique features that distinguish Cw*1701 from other HLA-C alleles include multiple point substitutions and an 18 nucleotide insertion in exon 5, which encodes the transmembrane domain. In a phylogenetic analysis of HLA-C sequences, Cw*1701 forms a third, distinct allelic lineage. A comparison of the transmembrane domain of Cw*1701 with other HLA-B and -C alleles reveals that duplications and deletions have been common in the evolution of these loci. A polymerase chain reaction based typing method was used to determine the distribution of this unusual allele in human populations. In contrast to the other two lineages of HLA-C alleles, the Cw*17 lineage is found at high frequencies only in populations of African descent. In addition, the HLA-B/Cw*17 haplotype diversity is higher in Africa.

Africa↗
PubMed2003

X-linked and lineage-dependent inheritance of coping responses to stress.

Coping-or how one routinely deals with stress-is a complex behavioral trait with bearing on chronic disease and susceptibility to psychiatric disorders. This complexity is a result of not only underlying multigenic factors, but also important non-genetic ones. The defensive burying (DB) test, although originally developed as a test of anxiety, can accurately measure differences in coping strategies by assaying an animal's behavioral response to an immediate threat with ethological validity. Using offspring derived from reciprocal crosses of two inbred rat strains differing in DB behaviors, we provide convergent phenotypic and genotypic evidence that coping styles are inherited in an X-linked fashion. We find that first-generation (F(1)) males, but not females, show maternally derived coping styles, and second-generation (F(2)) females, but not males, show significant differences in coping styles when separated by grandmaternal lineage. By using a linear modeling approach to account for covariate effects (sex and lineage) in QTL analysis, we map three quantitative trait loci (QTL) on the X Chromosome (Chr) ( Coping-1, Approach-1, and Approach-2) associated with coping behaviors in the DB paradigm. Distinct loci were associated with different aspects of coping, and their effects were modulated by both the sex and lineage of the animals, demonstrating the power of the general linear modeling approach and the important interplay of allelic and non-allelic factors in the inheritance of coping behaviors.

Adaptation, Psychological↗
PubMed2004

Sex- and lineage-specific inheritance of depression-like behavior in the rat.

The Wistar-Kyoto (WKY) rat exhibits physiological and behavioral similarities to endophenotypes of human depression. In the forced swim test (FST), a well-characterized antidepressant-reversible test for behavioral despair in rodents, WKYs express characteristics of behavioral despair; increased immobility, and decreased climbing. To map genetic loci linked to behavior in the FST, we conducted a quantitative trait loci (QTL) analysis of the segregating F2 generation of a WKY x Fisher 344 (F344) reciprocal intercross. Using linear-model-based genome scans to include covariate (sex or lineage)-by-QTL interaction effects, four significant QTL influencing climbing behavior were identified. In addition, we identified three, seven, and two suggestive QTL for climbing, immobility, and swimming, respectively. One of these loci was pleiotropic, affecting both immobility and climbing. As found in human linkage studies, several of these QTL showed sex- and/or lineage-dependent effects. A simultaneous search strategy identified three epistatic locus pairs for climbing. Multiple regression analysis was employed to characterize the joint contributions of these QTL and to clarify the sex- and lineage-dependent effects. As expected for complex traits, FST behavior is influenced by multiple QTL of small effect, each contributing 5%-10%, accounting for a total 10%-30% of the phenotypic variance. A number of loci mapped in this study share overlapping candidate regions with previously identified emotionality QTL in mice as well as with susceptibility loci recognized by linkage or genome scan analyses for major depression or bipolar disorder in humans. The presence of these loci across species suggests that these QTL may represent universal genetic factors contributing to mood disorders.

Animals↗
PubMed2005

Divergent non-LTR retrotransposon lineages from the genomes of scorpions (Arachnida: Scorpiones).

We screened across the taxonomic diversity of order Scorpiones (22 species belonging to 21 genera and 10 families) for the presence of seven different clades of non-LTR retrotransposons in their genomes using PCR with newly designed clade-specific consensus-degenerate hybrid oligonucleotide primers. Scorpion genomes were found to contain four known non-LTR retrotransposon clades: R1, I, Jockey, and CR1. In total, 35 fragments of reverse transcriptase genes of new elements from 22 scorpion species were obtained and analyzed for three clades, Jockey, I, and CR1. Phylogenies of different clades of elements were built using amino acid sequences inferred from 33 non-LTR retrotransposon clones. Distinct evolutionary lineages, with several major groups of the non-LTR retroelements were identified, showing significant variation. Four lineages were revealed in Jockey clade. The phylogeny of I clade showed strong support for the monophyletic origin of such group of elements in scorpions. Three separate lineages can be distinguished in the phylogenetic tree of CR1 clade. The large fraction of the isolated elements appeared to be defective.

Animals↗
PubMed2004

Positive selection in MAOA gene is human exclusive: determination of the putative amino acid change selected in the human lineage.

Monoamine oxidase A (MAOA) is the X-linked gene responsible for deamination and subsequent degradation of several neurotransmitters and other amines. Among other activities, the gene has been shown to play a role in locomotion, circadian rhythm, and pain sensitivity and to have a critical influence on behavior and cognition. Previous studies have reported a non-neutral evolution of the gene attributable to positive selection in the human lineage. To determine whether this selection was human-exclusive or shared with other species, we performed a population genetic analysis of the pattern of nucleotide variation in non-human species, including bonobo, chimpanzee, gorilla, and orangutan. Footprints of positive selection were absent in all analyzed species, suggesting that positive selection has been recent and unique to humans. To determine which human-unique genetic changes could have been responsible for this differential evolution, the coding region of the gene was compared between human, chimpanzee, and gorilla. Only one human exclusive non-conservative change is present in the gene: Glu151Lys. This human substitution affects protein dimerization according to a three-dimensional structural model that predicts a non-negligible functional shift. This is the only candidate position at present to have been selected to fixation in humans during an episode of positive selection. Divergence analysis among species has shown that, even under positive selection in the human lineage, the MAOA gene did not experience accelerated evolution in any of the analyzed lineages, and that tools such as K(a)/ K(s) would not have detected the selective history of the gene.

Amino Acid Sequence↗
PubMed2006

Characteristics of rat bone marrow cells differentiated into a liver cell lineage and dynamics of the transplanted cells in the injured liver.

BACKGROUND: Bone marrow cells (BMCs) have been shown to differentiate into a liver cell lineage, but little is known about their dynamics following transplantation. BMCs were cultured to investigate the expression of liver-specific genes in vitro and transplanted into in vivo liver-injury models to elucidate their dynamics in the liver. METHODS: The mRNA expression of various liver-specific genes in BMCs cocultured with hepatocytes was analyzed using reverse transcription-polymerase chain reaction. BMCs from transgenic rats expressing green fiuorescent protein were transplanted into the spleen of rat liver-injury models induced with 2-acetylaminofiuorene (2-AAF) or carbon tetrachloride (CCl4). BMCs were also transplanted directly into livers treated with CCl4 to determine which route is better for transplantation. RESULTS: BMCs differentiated into a liver cell lineage in vitro and expressed mRNAs consistent with mature hepatocytes, including albumin. The transplanted BMCs were found in the liver in the CCl4-induced injury model, but not in the 2-AAF-induced model. The hepatocyte growth factor and fibroblast growth factor mRNA levels in the liver were significantly higher in the CCl4-induced model than in the 2-AAF-induced model. Migration of BMCs to the liver was more effective following injection into the liver, rather than into the spleen. CONCLUSIONS: Cultured BMCs differentiated into a liver cell lineage are a potential source for cell transplantation. Transplantation is successful in the severely injured liver with a high level of expression of mRNAs for growth factors. Injection of BMCs directly into the liver is the preferred route of administration.

2-Acetylaminofluorene↗
PubMed2005

A novel genetic lineage differentiating RT-PCR as a useful tool in molecular epidemiology of foot-and-mouth disease in India.

Comparison of nucleotide sequences at the VP1 coding region of foot-and-mouth disease serotype Asia1 viruses from India has revealed two genetic lineages with emergence of a genetically divergent group in recent years. In this study a simple, fast, relatively costeffective multi-primer RT-PCR assay to differentiate genetic lineages of type Asia1 viruses was developed. Efforts were made in the design of novel lineage-specific primers and in optimization of the multi-primer assay protocol in conjunction with the use of the serotype specific primer for confirmation of serotype Asia1 virus. This assay promises to be an effective tool in molecular epidemiological investigation of FMD in the country.

Capsid Proteins↗
PubMed2006

Co-circulation of distinct genetic lineages of astroviruses in turkeys and guinea fowl.

Viruses belonging to the genus Astrovirus have been increasingly associated with enteritis in mammalian and avian species, including turkeys. More recently, astroviruses have also been detected in diseased guinea fowl. In turkeys, two genetically distinct types of astrovirus have been reported, namely turkey astrovirus 1 and 2 (TAstV1 and TAstV2). The prevalence and the pathogenesis of astrovirus infections in this species is currently unknown, with the exception of data generated in the USA. In the present report, we have demonstrated the co-circulation of distinct genetic lineages of astroviruses infecting turkeys and guinea fowl. The predominant lineage infecting turkeys is genetically related to the American TAstV2, but genetic variability within this lineage was demonstrated. Other isolates appeared to be either TastV1-related or unrelated to any other known isolate. Astroviruses infecting guinea fowl were more closely related to TAstV2, and interspecies transmissions between turkeys and guinea fowl is suggested as a possible mechanism by which these viruses may have evolved, based on the genetic data available. This investigation provides genetic and epidemiological information contributing to a better understanding of enteric viral infections in turkeys and guinea fowl.

Animals↗
PubMed2001

Diversification of hepatitis C viruses in South America reveals a novel genetic lineage.

Hepatitis C virus (HCV) has high genomic variability and, since its discovery, at least six different types and an increasing number of sub-types have been reported. Genotype 1 is the most prevalent genotype found in South America. Recent phylogenetic analysis of strains isolated in Uruguay revealed the presence of a different genetic lineage from major sub-types 1a and 1b. In order to study if type 1 HCV strains circulating in the South American region can be associated with this genetic lineage, sequence data obtained from the 5' non-coding region from 6 type 1 patients from Chile, were compared with sequences obtained from 12 type 1 Uruguayan and 9 type 1 Brazilian patients as well as 17 different strains of all types isolated elsewhere. The phylogenetic analysis revealed the existence of type 1 strains of this novel genetic lineage in all South American countries studied, and indicates a diversification of HCV viruses in the South American region.

5' Untranslated Regions↗
PubMed2007

mtDNA diversity and genetic lineages of eighteen cattle breeds from Bos taurus and Bos indicus in China.

In order to clarify the origin and genetic diversity of indigenous cattle breeds in China, we carried out phylogenetic analysis of representatives of those breeds by employing mitochondrial gene polymorphism. Complete cyt b gene sequences, 1140 bp in length, were determined for a total of 136 individuals from 18 different breeds and these sequences were clustered into two distinct genetic lineages: taurine (Bos taurus) and zebu (Bos indicus). In analysis of the cyt b gene diversity, Chinese cattle showed higher nucleotide (0.00923) and haplotype diversity (0.848) than the reports from other studies, and the animals from the taurine lineage indicated higher nucleotide diversity (0.00330) and haplotype diversity (0.746) than the ones from the zebu lineage (0.00136; 0.661). The zebu mtDNA dominated in the southern breeds (63.3-100%), while the taurine dominated in the northern breeds (81.8-100%). Six cattle breeds from the central area of China exhibited intermediate frequencies of zebu mtDNA (25-71.4%). This polymorphism revealed a declining south-to-north gradient of female zebu introgression and a geographical hybrid zone of Bos taurus and Bos indicus in China.

Animals↗
PubMed1991

Population dynamics of "null" and Thy1lo lymphocytes in mouse bone marrow: genesis of cells with natural killer cell lineage characteristics.

The population dynamics of "null" small lymphocytes lacking B and T lineage markers in mouse bone marrow have been examined using a combination of immunolabeling and hydroxyurea (HU) deletion techniques. The binding of the B lineage-associated mAb, 14.8, and anti-Thy1.2 to bone marrow cells has been detected radioautographically. Null cells lacking 14.8 and Thy1.2 determinants (14.8- Thy1-) formed a substantial subset (12-14%) of bone marrow small lymphocytes, representing 0.5 x 10(6) cells per femur (2-3% of nucleated cells). HU treatment revealed an exceptionally rapid turnover of the null small lymphocyte population (T1/2, 7.5 hr) compared with 14.8+ cells (T1/2, 20.5 hr) and Thy1+ cells (T1/2, 53 hr). Small lymphocytes bearing low intensities of Thy1 (Thy1lo) were also rapidly renewed (T1/2, 28 hr) whereas those with high intensities of Thy1 (Thy1hi) were renewed only slowly (T1/2, 123 hr). During ontogeny, null small lymphocytes first appeared in the fetal liver by Day 11 and the fetal spleen by Day 16, but increased rapidly in the bone marrow in early postnatal life. Double immunolabeling techniques demonstrated that 10% of null small lymphocytes in the bone marrow expressed NK1.1 antigen, while larger proportions bound to tumor (YAC.1) cells in vitro and displayed Fc receptors. The NK1.1-bearing fraction of null small lymphocytes in bone marrow was depleted by HU treatment only after an initial delay. NK1.1 was also expressed on subsets of Thy1lo cells and Thy1hi cells. The results have revealed the continuous production in mouse bone marrow of null and Thy1lo small lymphocytes, totaling 1-3 x 10(7) cells/day and 1.2 x 10(6) cells/day, respectively. The findings suggest that the large-scale production of null lymphocytes in mouse bone marrow includes the genesis of NK lineage cells which express NK1.1 and Thy1lo during a period of terminal maturation.

Age Factors↗
PubMed1985

Cell lineage of zebrafish blastomeres. III. Clonal analyses of the blastula and gastrula stages.

Aspects of the early lineages of blastomeres in the embryo of the zebrafish, Brachydanio rerio have been described. Because of the optical clarity of the embryo, lineages of selected cells can be followed directly by microscopy through many cell divisions. Also, it is shown here that the fluorescent molecules fluorescein-dextran and rhodamine-horseradish peroxidase can be used as cell lineage tracers, marking the clonal progeny of founding blastomeres. The labeled cells can be easily visualized in the live embryo, and utilizing a sensitive video camera to amplify fluorescence, the same clone may be examined repeatedly while the cells divide and migrate. Cells that descend from a single blastomere remain closely associated together through the end of the blastula stage. At the time when epiboly begins (early gastrula) cells in the labeled clone scatter and become dispersed among unlabeled cells. It has been observed that there is no invariant mapping of the embryo's midline (determined by the position of the embryonic shield in the gastrula) with respect to the early planes of cleavage. This finding shows that in the zebrafish the region of the embryo that a cell will occupy is not specified by the cell's early ancestory.

Animals↗
PubMed1985

Cell lineage analysis in ascidian embryos by intracellular injection of a tracer enzyme. II. The 16- and 32-cell stages.

Cell lineages during development of ascidian embryos were analyzed by injecting horseradish peroxidase as a tracer enzyme into identified cells of the 16-cell and 32-cell stage embryos of Halocynthia roretzi. Most of the blastomeres of these embryos developed more kinds of tissues than have hitherto been reported, and therefore, the developmental fates of each blastomere are more complex. It has been thought that every blastomere of the 64-cell stage ascidian embryo gives rise to only one kind of tissues, but the finding that the several blastomeres at the 32-cell stage developed into at least three different kinds of tissues, clearly indicates that the stage at which the fates of every blastomere are determined to one tissue is later than the 64-cell stage. The results also clearly demonstrate that muscle cells are derived not only from B-line cells (B5.1, B5.2, B6.3, and B6.4) but also from A-line cells (A5.2 and A6.4) and b-line cells (b5.3 and b6.5). Based on the present analysis as well as other studies, complete cell lineages of muscle cells up to their terminal differentiation have been proposed. In addition, lineages of nervous system, notochord, and epidermis are also discussed.

Animals↗
PubMed1988

Development of the central nervous system of the larva of the ascidian, Ciona intestinalis L. I. The early lineages of the neural plate.

The early lineages of the larval central nervous system (CNS) of the ascidian, Ciona intestinalis, have been traced using scanning electron microscopy (SEM) of embryos fixed at 12-min intervals. The CNS precursors lie superficially, exposed for a long portion (9.3 hr of 42%) of embryonic development, in the neural plate. In the 64-cell stage embryo the neural plate contains 10 cells; in all but the first vegetal division these divide with transverse cleavage planes. Synchrony is progressively lessened, but temporal sequence is always exact. Successive divisions occur initially at 30-min intervals. Our analysis confirms existing lineage descriptions for the neural plate up to the end of gastrulation and advances the lineage record through the crucial and temporally complex ninth cleavage, during which cells divide by the following rules: medial cells in each row divide first; the anterior row of vegetal daughter cells divides before their posterior siblings; the posterior row of animal daughter cells divide before their anterior siblings. All cells attain their 10th generation, but four cannot be followed by SEM. In preparation for neurulation the neural plate then comprises 76 cells, forming up to four rows each of eight vegetal hemisphere cells located on the dorsal surface of the embryo, anterior to the blastopore, and eight rows each of six animal hemisphere cells, located anterior to the rows of eight. The temporal and spatial patterns of early cleavage stages have been confirmed in vivo by observations using Nomarski optics.

Animals↗
PubMed1988

Development of the central nervous system of the larva of the ascidian, Ciona intestinalis L. II. Neural plate morphogenesis and cell lineages during neurulation.

We describe the lineage and morphogenesis of neural plate cells in the ascidian, Ciona intestinalis, from reconstructed cell maps of embryos at 12-min intervals during and after neurulation, between 31 and 61% of embryonic development. Neurulation commences in a posterior to anterior wave following in the wake of the ninth cleavage, when all cells, except possibly four, are in their 10th generation. The neural plate then comprises 76 cells, in up to four posterior rows each of eight vegetal-hemisphere cells, and eight anterior rows each of six animal-hemisphere cells. Two cells are lost from the neural plate to the muscle cell line during neurulation and four cells are gained from ectoderm outside the plate. All cells become wedge-shaped. Simple, stereotyped positional changes transform cells from lateral locations in the plate to posterior locations in the tube; bilateral partners shear their midline positions to form the keel, and ectodermal cells zipper up dorsally to form the capstone, of a tube which is four cells in cross section posteriorly, but more complex anteriorly. Neither cell death nor migration occur during neurulation. Divisions become asynchronous and the cell-cycle extends; 170 10th- to 12th-generation cells exist by the time the neural tube becomes completely internalized. Generally, only one further division is required to complete the lineage analysis, two at the most. Neural plate cell divisions were invariant using our observational methods, and their lineage is compared with that from recent studies of H. Nishida (1987, Dev. Biol. 121, 526-541).

Age Factors↗
PubMed1989

Determination and regulation in the pigment cell lineage of the ascidian embryo.

The brain of the ascidian larva comprises two pigment cells, termed the ocellus melanocyte and the otolith melanocyte. Cell lineage analysis has shown that the two bilateral pigment lineage cells (a-line blastomeres) in the animal hemisphere give rise to these melanocytes in a complementary manner. The results of the present investigation suggest that the specification of the fate of pigment cells proceeds in two distinct steps. First, the determination of pigment lineage cells requires an inductive interaction from the vegetal blastomeres of the A-line. Cell dissociation experiments demonstrated that the inductive interaction is completed by the midgastrula stage. However, the two bilaterally positioned cells destined to become the pigment cells in the first step are still equipotent at this stage in that they can give rise to either the ocellus or otolith. Thus, they constitute what is termed an "equivalence group." In the second step, the individual fates of the two cells that compose the equivalence group are determined. Namely, one cell develops into an ocellus and the other cell develops into an otolith. Photoablation of one of the pigment precursor cells at various stages indicated that the second step of determination occurs at the midtailbud stage. It is suggested that the cue to choose one of the alternative developmental pathways may be positional information that exists along the anteroposterior axis. The second step of determination is thought to be mediated by a hierarchical interaction. In the absence of this interaction, melanocyte specification proceeds along the dominant pathway that results in the differentiation of an ocellus.

Animals↗