Search results for "phylogeny"
showing 10 items of 1398 documents
The human complement component C8B gene: structure and phylogenetic relationship
1993
The eighth component of human complement (C8) is a serum protein that consists of three chains (alpha, beta and gamma), encoded by three separate genes, viz., C8A, C8B, and C8G. In serum, the beta-subunit is non-covalently bound to the disulfide-linked alpha-gamma subunit. Using a full-length C8 beta cDNA probe, we isolated several clones from human genomic lambda DNA libraries. Four lambda clones covering the complete cDNA sequence were characterized by TaqI restriction mapping and were "shotgun" subcloned into M13. C8 beta-cDNA-positive clones were partially sequenced to characterize the 12 exons of the gene with sizes from 69 to 347 bp. All intron-exon junctions followed the GT-AG rule. …
The evolution of human synteny 4 by mapping sub-chromosomal specific probes in Primates
2014
Comparative cytogenetic data concerning the orthologue to human chromosome 4 in primates shows that this chromosome is conserved between humans and non-human primates. However, the degree of conservation is not as high as previously estimated. In primates it is as a rule a large submetacentric chromosome but many exceptions are known especially in taxa characterized by a high level of chromosomal rearrangements. The rearrangements that have been visualized by chromosome painting so far, which are mostly interchromosomal changes, are in fact only a fraction of the actual chromosomal changes that have occurred during evolution. Intrachromosome changes can be analysed through classical cytogen…
Comparative Genomics of the RBR Family, Including the Parkinson's Disease–Related Gene Parkin and the Genes of the Ariadne Subfamily
2002
Genes of the RBR family are characterized by the RBR signature (two RING finger domains separated by an IBR/DRIL domain). The RBR family is widespread in eukaryotes, with numerous members in animals (mammals, Drosophila, Caenorhabditis) and plants (Arabidopsis). But yeasts, such as Saccharomyces cerevisiae or Schizosaccharomyces pombe, contain only two RBR genes. We determined the phylogenetic relationships and the most likely orthologs in different species of several family members for which functional data are available. These include: (1) parkin, whose mutations are involved in forms of familial Parkinson's disease; (2) the ariadne genes, recently characterized in Drosophila and mammals;…
Parkin and relatives: the RBR family of ubiquitin ligases
2004
Mutations in the parkin gene cause autosomal-recessive juvenile parkinsonism. Parkin encodes a ubiquitinprotein ligase characterized by having the RBR domain, composed of two RING fingers plus an IBR/DRIL domain. The RBR family is defined as the group of genes whose products contain an RBR domain. RBR family members exist in all eukaryotic species for which significant sequence data is available, including animals, plants, fungi, and several protists. The integration of comparative genomics with structural and functional data allows us to conclude that RBR proteins have multiple roles, not only in protein quality control mechanisms, but also as indirect regulators of transcription. A recent…
Partial Sequence Homogenization in the 5S Multigene Families May Generate Sequence Chimeras and Spurious Results in Phylogenetic Reconstructions
2014
Multigene families have provided opportunities for evolutionary biologists to assess molecular evolution processes and phylogenetic reconstructions at deep and shallow systematic levels. However, the use of these markers is not free of technical and analytical challenges. Many evolutionary studies that used the nuclear 5S rDNA gene family rarely used contiguous 5S coding sequences due to the routine use of head-to-tail polymerase chain reaction primers that are anchored to the coding region. Moreover, the 5S coding sequences have been concatenated with independent, adjacent gene units in many studies, creating simulated chimeric genes as the raw data for evolutionary analysis. This practice…
Molecular analysis of METTL1, a novel human methyltransferase-like gene with a high degree of phylogenetic conservation.
1999
A novel human gene, METTL1, has been identified by its sequence similarity to the yeast ORF YDL201w. The human cDNA and the genomic structure of METTL1 have been analyzed. The transcript contains 1292 nucleotides and codes for a protein of 276 amino acids. The gene consists of seven exons and extends over 3.5 kb. The six introns vary in length between 93 and 1137 nucleotides. The gene is transcribed in a large variety of organs and tissues and shows differential splicing of two exons, giving rise to at least three different transcripts. The METTL1 gene was assigned to chromosome 12q13 by radiation hybrid mapping. The METTL1 gene product shows high sequence similarities to putative proteins …
Plasticity of human chromosome 3 during primate evolution.
2004
Comparative mapping of more than 100 region-specific clones from human chromosome 3 in Bornean and Sumatran orangutans, siamang gibbon, and Old and New World monkeys allowed us to reconstruct ancestral simian and hominoid chromosomes. A single paracentric inversion derives chromosome 1 of the Old World monkey Presbytis cristata from the simian ancestor. In the New World monkey Callithrix geoffroyi and siamang, the ancestor diverged on multiple chromosomes, through utilizing different breakpoints. One shared and two independent inversions derive Bornean orangutan 2 and human 3, implying that neither Bornean orangutans nor humans have conserved the ancestral chromosome form. The inversions, f…
Amplified fragment length polymorphisms and sequence data in the phylogenetic analysis of polyploids: multiple origins of Veronica cymbalaria (Planta…
2007
Summary • The origin of polyploid Veronica cymbalaria (Plantaginaceae) was investigated using DNA sequence data and amplified fragment length polymorphism (AFLP) fingerprints to reveal the parentage of this taxon. The use of AFLP fingerprints in phylogenetic analysis is problematic and various methods have therefore been compared. • DNA sequence data (for the internal transcribed spacer (ITS) region and the plastid trnL-F region (trnL intron, 3’exon, and trnL-F spacer)) and polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis of the ITS region suggested a reliable hypothesis for the evolution of the V. cymbalaria complex. This hypothesis allowed evaluation …
Phylogenetic relationships within the family Halomonadaceae based on comparative 23S and 16S rRNA gene sequence analysis.
2010
A phylogenetic study of the family Halomonadaceae was carried out based on complete 16S rRNA and 23S rRNA gene sequences. Several 16S rRNA genes of type strains were resequenced, and 28 new sequences of the 23S rRNA gene were obtained. Currently, the family includes nine genera (Carnimonas, Chromohalobacter, Cobetia, Halomonas, Halotalea, Kushneria, Modicisalibacter, Salinicola and Zymobacter). These genera are phylogenetically coherent except Halomonas, which is polyphyletic. This genus comprises two clearly distinguished clusters: group 1 includes Halomonas elongata (the type species) and the species Halomonas eurihalina, H. caseinilytica, H. halmophila, H. sabkhae, H. almeriensis, H. hal…
Phylogeny of the genus Kluyveromyces inferred from the mitochondrial cytochrome-c oxidase II gene.
2000
A phylogenetic analysis of 17 species belonging to the genus Kluyveromyces and 12 reference and outgroup species was performed using mitochondrial cytochrome-c oxidase II gene sequences. The genus Kluyveromyces appears as a polyphyletic taxon formed by species included within the following four main groups. The Kluyveromyces phaffii group encompasses the species Kluyveromyces blattae, K. phaffii and Kluyveromyces yarrowii. The Kluyveromyces marxianus group is a monophyletic group consisting of the species Kluyveromyces aestuarii, Kluyveromyces dobzhanskii, Kluyveromyces lactis, K. marxianus and Kluyveromyces wickerhamii. The monophyletic Kluyveromyces thermotolerans group is formed by K. th…