Research Article

Related GMR Articles

05/19/2004
Amphibians; Evolution; Gene redundancy; Polyploidy; Speciation

The evolution of the metazoa has been characterized by gene redundancy, generated by polyploidy, tandem duplication and retrotransposition. Polyploidy can be detected by looking for duplicated chromosomes or segments of orthologous chromosomes in post-polyploid animals. It has been proposed that the evolutionary role of polyploidy is to provide extra-copies of genes, whose subsequent ... more

M.Luiza Beçak; L.Setsuo Kobashi
01/17/2012
Cytomixis; Houttuynia cordata; Meiosis; Microsporogenesis; Polyploidy

Houttuynia cordata (Saururaceae) is a leaf vegetable and a medicinal herb througout much of Asia. Cytomixis and meiotic abnormalities during microsporogenesis were found in two populations of H. cordata with different ploidy levels (2n = 38, 96). Cytomixis occurred in pollen mother cells during meiosis at high frequencies and with variable degrees of chromatin/ ... more

J.Z. Guan; J.J. Wang; Z.H. Cheng; Y. Liu; Z.Y. Li
01/17/2012
Cytomixis; Meiosis; Microsporogenesis; Pinellia ternata; Polyploidy

Pinellia ternata is an important traditional Chinese medicinal plant. Its different populations in China have various ploidy levels, based on x = 13, as well as extensive aneuploid series. The microsporogenesis process was observed in specimens from three populations from three regions of Hubei Province; they were characterized by normal and abnormal meiotic divisions in ... more

Y. Liu; R.K. Hui; R.N. Deng; J.J. Wang; M. Wang; Z.Y. Li
11/08/2002
Apomixis origin; Centers of diversity; Electrophoresis; Evolution; Interspecific hybridization; Polyploidy; Unreduced gametes

About 98 species of Manihot are known. All of them are native to the New World and are concentrated in four regions in Brazil and Central America. All the Manihot species so far examined have 2n = 36 chromosomes. Interspecific hybrids between cassava and its wild relatives show relatively normal meiosis, and further generations can be obtained. Electrophoresis shows ... more

N.M.A. Nassar
03/06/2002
Evolution; Future selection; Immune system; Lamarck & Darwin legacies; Somatic selection
H. Hoenigsberg
09/30/2003
Cell biology conservation; Darwinian evolution; Evolution; Prokaryotes

Our theory is embarrassingly simple. What made today’s prokaryotes and modern cyanobacteria so robust is the fact that in their origin, back in the Archean (3 billion years ago), selection did not play a central role in evolution, it had only a transitory role. Asexual reproduction, mutation, drift and sampling variance in local demes were more important especially when they were ... more

H. Hoenigsberg
10/06/2006
Evolution; Exotic animals; Genetic diversity; Molecular genetic

We examined the variation in mitochondrial DNA by sequencing the D-loop region in wild and domestic (large-white breed) pigs, in hybrids between domestic and wild pigs, and in Monteiro pigs. A D-loop fragment of approximately 330 bp was amplified by PCR. Sequencing of DNA amplicons identified haplotypes previously described as European and Asian types. Monteiro pigs and wild pigs had ... more

S.F. Grossi; J.F. Lui; J.E. Garcia; F.V. Meirelles
10/25/2013
Ctenomyidae; Cytochrome b; Evolution; Molecular phylogeny

The genus Ctenomys (Rodentia: Ctenomyidae) shows several taxonomic inconsistencies. In this study, we used an integrative approach including DNA sequences, karyotypes, and geometric morphometrics to evaluate the taxonomic validity of a nominal species, Ctenomys bicolor, which was described based on only one specimen in 1912 by Miranda Ribeiro, and since then neglected. ... more

J.F.B. Stolz; G.L. Gonçalves; L. Leipnitz; T.R.O. Freitas
03/07/2013
Evolution; FISH; Neotropical region; Systematic phylogeny

A species complex hypothesis involving Astyanax fasciatus from southern Brazil was tested using 12S mtDNA sequences. Phylogenetic inferences were performed with maximum likelihood, maximum parsimony and Bayesian as phylogenetic methods and Hemigrammus bleheri as the outgroup. Besides 11 sequences from A. fasciatus, the data set was comprised of other partial ... more

D.A. Matoso; M. da Silva; R.F. Artoni; R.A. Torres
01/15/2015
Evolution; Genetic relationship; Local cultivar; Peach; Population structure; Simple sequence repeat (SSR)

The fruit peach originated in China and has a history of domestication of more than 4000 years. Numerous local cultivars were selected during the long course of cultivation, and a great morphological diversity exists. To study the diversity and genetic background of local peach cultivars in China, a set of 158 accessions from different ecological regions, together with 27 modern varieties ... more

Z.J. Shen; R.J. Ma; Z.X. Cai; M.L. Yu; Z. Zhang

Pages