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showing 10 items of 14693 documents
Evolution of the immune system influences speciation rates in teleost fishes.
2016
Teleost fishes constitute the most species-rich vertebrate clade and exhibit extensive genetic and phenotypic variation, including diverse immune defense strategies. The genomic basis of a particularly aberrant strategy is exemplified by Atlantic cod, in which a loss of major histocompatibility complex (MHC) II functionality coincides with a marked expansion of MHC I genes. Through low-coverage genome sequencing (9–39×), assembly and comparative analyses for 66 teleost species, we show here that MHC II is missing in the entire Gadiformes lineage and thus was lost once in their common ancestor. In contrast, we find that MHC I gene expansions have occurred multiple times, both inside and outs…
The maternal genetic make-up of the Iberian Peninsula between the Neolithic and the Early Bronze Age
2017
Agriculture first reached the Iberian Peninsula around 5700 BCE. However, little is known about the genetic structure and changes of prehistoric populations in different geographic areas of Iberia. In our study, we focus on the maternal genetic makeup of the Neolithic (~ 5500–3000 BCE), Chalcolithic (~ 3000–2200 BCE) and Early Bronze Age (~ 2200–1500 BCE). We report ancient mitochondrial DNA results of 213 individuals (151 HVS-I sequences) from the northeast, central, southeast and southwest regions and thus on the largest archaeogenetic dataset from the Peninsula to date. Similar to other parts of Europe, we observe a discontinuity between hunter-gatherers and the first farmers of the Neol…
Cytoskeletal transgelin 2 contributes to gender-dependent adipose tissue expandability and immune function
2019
During adipogenesis, preadipocytes' cytoskeleton reorganizes in parallel with lipid accumulation. Failure to do so may impact the ability of adipose tissue (AT) to shift between lipid storage and mobilization. Here, we identify cytoskeletal transgelin 2 (TAGLN2) as a protein expressed in AT and associated with obesity and inflammation, being normalized upon weight loss. TAGLN2 was primarily found in the adipose stromovascular cell fraction, but inflammation, TGF-β, and estradiol also prompted increased expression in human adipocytes. Tagln2 knockdown revealed a key functional role, being required for proliferation and differentiation of fat cells, whereas transgenic mice overexpressing Tagl…
Neolithic animal domestication as seen from ancient DNA
2018
Abstract In recent years, archaeological, archaeozoological and population genetic studies have increasingly converged on a southwest Asian origin for the four Neolithic farm animals: cattle, sheep, goats, and pigs. The power of ancient DNA studies lies in the possibility of tracking the genetic traces of major demographic processes, such as domestication itself and subsequent migration, at their spatiotemporal sources. In doing so, they are bypassing more recent events, which may have blurred ancient signals until the point of disappearance. Past ancient DNA studies have mostly relied on a single, powerful and – even for degraded ancient samples – easily accessible genetic marker: the mate…
Ethical Aspects of Nuclear and Mitochondrial DNA Transfer
2016
Somatic cell nuclear transfer (SCNT) (cloning), as a reproductive or therapeutic method, and mitochondrial DNA transfer, as a method to prevent the transmission of mitochondrial diseases, are analyzed in this paper from a bioethics perspective. The licit purpose of being able to treat certain diseases, as in the case of SCNT, cannot justify, in any case, resorting to illicit means such as the manipulation, selection, and elimination of human embryos in the blastocyst phase, by using cell lines obtained from them. Crossing this line paves the way (as utilitarian ethics advocates) to assuming any cost in scientific experimentation so long as satisfactory results are obtained. With mitochondr…
Phylogeny of Syndermata (syn. Rotifera): Mitochondrial gene order verifies epizoic Seisonidea as sister to endoparasitic Acanthocephala within monoph…
2015
Abstract A monophyletic origin of endoparasitic thorny-headed worms (Acanthocephala) and wheel-animals (Rotifera) is widely accepted. However, the phylogeny inside the clade, be it called Syndermata or Rotifera, has lacked validation by mitochondrial (mt) data. Herein, we present the first mt genome of the key taxon Seison and report conflicting results of phylogenetic analyses: while mt sequence-based topologies showed monophyletic Lemniscea (Bdelloidea + Acanthocephala), gene order analyses supported monophyly of Pararotatoria (Seisonidea + Acanthocephala) and Hemirotifera (Bdelloidea + Pararotatoria). Sequence-based analyses obviously suffered from substitution saturation, compositional …
Discovering new proteins in plant mitochondria by RNA editing simulation
2016
In plant mitochondria an essential mechanism for gene expression is RNA editing, often influencing the synthesis of functional proteins. RNA editing alters the linearity of genetic information transfer. Indeed it causes differences between RNAs and their coding DNA sequences that hinder both experimental and computational research of genes. Therefore common software tools for gene search, successfully applied to find canonical genes, often fail in discovering genes encrypted in the genome of plants. Here we propose a novel strategy useful to identify candidate coding sequences resulting from possible editing substitutions. In particular, we consider c!u substitutions leading to the creation…
Comparing three complete mitochondrial genomes of the moss genus Orthotrichum Hedw.
2016
Here, we present a comparative analysis of the mitochondrial genome of three representatives of Orthotrichum Hedw (Bryophyta): two populations of O. diaphanum and one of the related species, namely O. macrocephalum. Their mitochondrial genomes share the same gene content and gene order, and are furthermore structurally identical to those of other arthrodontous mosses. The mitogenome of the allopatric samples of O. diaphanum differ in 0.1% of their sequence, with protein coding genes holding five mutations, including two non-synonymous changes. The divergence between the mitogenomes of the two species, O. diaphanum and O. macrocephalum, is 0.4%. Within a broader sampling of the Orthotrichace…
Genetic Analysis of Human Preimplantation Embryos
2016
Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assis…
A dual role of caspase-8 in triggering and sensing proliferation-associated DNA damage, a key determinant of liver cancer development.
2017
Summary Concomitant hepatocyte apoptosis and regeneration is a hallmark of chronic liver diseases (CLDs) predisposing to hepatocellular carcinoma (HCC). Here, we mechanistically link caspase-8-dependent apoptosis to HCC development via proliferation- and replication-associated DNA damage. Proliferation-associated replication stress, DNA damage, and genetic instability are detectable in CLDs before any neoplastic changes occur. Accumulated levels of hepatocyte apoptosis determine and predict subsequent hepatocarcinogenesis. Proliferation-associated DNA damage is sensed by a complex comprising caspase-8, FADD, c-FLIP, and a kinase-dependent function of RIPK1. This platform requires a non-apop…