Gender dependent and independent morphological dimorphism in sexual and apomictic Antennaria monocephala sensu lato

1991 ◽  
Vol 69 (7) ◽  
pp. 1433-1448 ◽  
Author(s):  
J. G. Chmielewski ◽  
C. C. Chinnappa
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Reproductive Biology ◽  
Chromosome Numbers ◽  
Evolutionary History ◽  
Multivariate Analyses ◽  
Reproductive Mode ◽  
Polyploid Complex ◽  
Adaxial Surface ◽  
History Of

Taxa included in the Antennaria monocephala DC. polyploid complex were previously circumscribed at the specific, subspecific, or varietal levels without concensus. The purpose of this phenetic study was to construct a taxonomy that not only reflects the presumed evolutionary history of the complex but also presents a taxonomy that is both functional and informative, regardless of an individual's gender or more importantly, the reproductive mode of the population. The rank of subspecies (A. monocephala ssp. monocephala and A. monocephala ssp. angustata (Green) Hultén) was accepted as the most appropriate level of gender independent circumscription that satisfied the purpose of the phenetic study. These subspecies differ with respect to tomentum, chromosome number, reproductive biology, and (in part) provenance. The former taxon, A. monocephala ssp. monocephala, is a sexual diploid (2n = 28); the latter taxon, A. monocephala ssp. augustata, is an apomictic polyploid, with chromosome numbers ranging from tetraploid (2n = 56) to octoploid (2n = 112). In A. monocephala ssp. monocephala the adaxial surface of the basal and cauline leaves is glabrous-strigose, as is the stem. In A. monocephala ssp. angustata the adaxial surface of both basal and cauline leaves is floccose-tomentose, as is the surface of the stem. Key words: Antennaria monocephala polyploid complex, multivariate analyses.

The Antennaria frieseana (Asteraceae: Inuleae) polyploid complex: morphological variation in sexual and agamospermous taxa

1994 ◽  
Vol 72 (7) ◽  
pp. 1018-1026 ◽  
Author(s):  
Jerry G. Chmielewski
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Reproductive Biology ◽  
Morphological Variation ◽  
Polyploid Complex ◽  
Corolla Length

The Antennaria frieseana (Trautv.) Ekman polyploid complex has been evaluated on numerous occasions without concensus to either the taxa that should be included or their proper ranks. The purpose of this phenetic study was to present a taxonomy for the polyploid complex that is not only independent of a knowledge of chromosome number and reproductive biology but that concurrently reflects morphological variation associated with each. The rank of subspecies (A. frieseana ssp. frieseana and A. frieseana ssp. alaskana (Malte) Hultén) was accepted as the most appropriate level of circumscription that satisfied the purpose of the phenetic study and was supported by the analysis. These subspecies differ with respect to the length of the involucre, inner phyllary length, pappus length, corolla length (the latter subspecies being typically smaller than the former), chromosome number, reproductive biology, and (in part) provenance. Antennaria frieseana ssp frieseana is an agamospermous polyploid, represented by pentaploid (2n = 70) and hexaploid (2n = 84) cytotypes. Antennaria frieseana ssp. alaskana is sexual, probably partially agamospermous (tetraploid cytotype), and either diploid (2n = 28) or tetraploid (2n = 56). Key words: Antennaria frieseana, morphological variation, apomicts, sexual, agamospermy.

Reconstructing ancestral chromosome numbers and inflorescence features in Eleusininae (Poaceae: Chloridoideae: Cynodonteae)

2020 ◽  
Vol 193 (3) ◽  
pp. 402-418
Author(s):  
Raquel B Chiavegatto ◽  
Angelino Carta ◽  
Diego G S Pereira ◽  
Flavio R G Benites ◽  
Vânia H Techio ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Evolutionary History ◽  
Basic Chromosome Number ◽  
High Rate ◽  
Recent Common Ancestor ◽  
Basic Chromosome ◽  
Most Recent Common Ancestor ◽  
Chromosome Number Evolution ◽  
History Of

Abstract The chromosome number in Poaceae has changed widely over 77 Myr of evolution and polyploidization. Chromosome number changes can suggest a high rate of diversification and evolutionary novelties, and such changes can contribute to speciation. Despite this, chromosome numbers alone do not allow the evolutionary history of a group to be traced. Combined phylogenetic and karyological analyses can clarify the evolutionary history of taxa and allow taxonomic relationships and hierarchical levels to be inferred. The subtribe Eleusininae is the largest of the subfamily Chloridoideae. This study aims to reconstruct their chromosome number evolution, for which ChromEvol 2.0 software was used. Haploid chromosome numbers of Eleusininae were retrieved from the literature, and a consensus phylogenetic tree of Eleusininae was reconstructed. It was possible to infer 41 events of chromosome rearrangements along the evolutionary history of Eleusininae, according to the probabilistic model used. Chromosome number evolution in Eleusininae was mainly influenced by polyploidy events. The ancestral basic chromosome number for Eleusininae was p = 6, but the most recent common ancestor showed p2 = 10. In addition, some derived basic chromosome numbers, such as x = 9, arose through dysploidy, whereas x = 20 was generated via polyploidy.

scholarly journals Genome-specific histories of divergence and introgression between an allopolyploid unisexual salamander lineage and two sexual species

2018 ◽  
Author(s):  
Robert D. Denton ◽  
Ariadna E. Morales ◽  
H. Lisle Gibbs
Keyword(s):  
Genetic Variation ◽  
Evolutionary History ◽  
Parental Species ◽  
Extended Period ◽  
Reproductive Mode ◽  
Mapping Method ◽  
Genetic Introgression ◽  
Sexual Species ◽  
History Of ◽  
Genomic Material

AbstractQuantifying genetic introgression between sexual species and polyploid lineages traditionally thought to be asexual is an important step in understanding what factors drive the longevity of putatively asexual groups. However, the presence of multiple distinct subgenomes within a single lineage provides a significant logistical challenge to evaluating the origin of genetic variation in most polyploids. Here, we capitalize on three recent innovations—variation generated from ultraconserved elements (UCEs), bioinformatic techniques for assessing variation in polyploids, and model-based methods for evaluating historical gene flow—to measure the extent and tempo of introgression over the evolutionary history of an allopolyploid lineage of all-female salamanders and two ancestral sexual species. We first analyzed variation from more than a thousand UCEs using a reference mapping method developed for polyploids to infer subgenome specific patterns of variation in the all-female lineage. We then used PHRAPL to choose between sets of historical models that reflected different patterns of introgression and divergence between the genomes of the parental species and the same genomes found within the polyploids. Our analyses support a scenario in which the genomes sampled in unisexuals salamanders were present in the lineage ∼3.4 million years ago, followed by an extended period of divergence from their parental species. Recent secondary introgression has occurred at different times between each sexual species and their representative genomes within the unisexuals during the last 500,000 years. Sustained introgression of sexual genomes into the unisexual lineage has been the defining characteristic of their reproductive mode, but this study provides the first evidence that unisexual genomes have also undergone long periods of divergence without introgression. Unlike other unisexual, sperm-dependent taxa in which introgression is rare, the alternating periods of divergence and introgression between unisexual salamanders and their sexual relatives could reveal the scenarios in which the influx of novel genomic material is favored and potentially explain why these salamanders are among the oldest described unisexual animals.

Obligatory amphimixis and variation in chromosome number within and among South American populations of Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 (Nematoda: Pratylenchidae)

Nematology ◽  
2005 ◽  
Vol 7 (5) ◽  
pp. 783-787 ◽  
Author(s):  
Géraldine Anthoine ◽  
Didier Mugniéry
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Experimental Approach ◽  
Taxonomic Status ◽  
Reproductive Mode ◽  
South American ◽  
Complementary Information ◽  
Haploid Chromosome Number ◽  
Nacobbus Aberrans

AbstractThere are conflicting opinions concerning the reproductive mode and the taxonomic status of Nacobbus aberrans, so we have addressed these issues by an experimental approach based on the inoculation of immature and vermiform females in in vitro conditions. Complementary information on chromosome number was provided. Five South American populations of Nacobbus aberrans were tested. No population was observed to be able to reproduce by parthenogenesis in in vitro conditions. The basic haploid chromosome number seems to be seven, at least for four of the five populations studied. However, all populations had individuals with haploid chromosome numbers ranging from five to eight, six to eight being the most frequent number, regardless of the 'race' group or the native country. The variation in the chromosome number suggests that N. aberrans may be considered as a set of different karyological genetic entities.

scholarly journals Terrestriality and bacterial transfer: A comparative study of gut microbiomes in sympatric Malagasy mammals

2018 ◽  
Author(s):  
Amanda C. Perofsky ◽  
Rebecca J. Lewis ◽  
Lauren Ancel Meyers
Keyword(s):  
Evolutionary History ◽  
Multivariate Analyses ◽  
Horizontal Transmission ◽  
Primate Species ◽  
Mammal Species ◽  
Shared History ◽  
Ecological Predictors ◽  
Captive Populations ◽  
History Of ◽  
Lemur Species

AbstractThe gut microbiomes of mammals appear to mirror their hosts’ phylogeny, suggesting a shared history of co-speciation. Yet, much of this evidence stems from comparative studies of distinct wild or captive populations that lack data for disentangling the relative influences of shared phylogeny and environment. Here, we present phylogenetic and multivariate analyses of gut microbiomes from six sympatric (i.e., co-occurring) mammal species inhabiting a 1-km2 area in western Madagascar—three lemur and three non-primate species—that consider genetic, dietary, and ecological predictors of microbiome functionality and composition. Host evolutionary history, indeed, appears to drive gut microbial patterns among distantly related species. However, we also find that diet—reliance on leaves versus fruit—is the best predictor of microbiome similarity among closely related lemur species, and that host substrate preference—ground versus tree— constrains horizontal transmission via incidental contact with feces, with arboreal species harboring far more distinct communities than those of their terrestrial and semi-terrestrial counterparts.

Organogénie de la feuille du Begonia radicans Vellozo et du Begonia scabrida (Begoniaceae)

1992 ◽  
Vol 70 (6) ◽  
pp. 1107-1122 ◽  
Author(s):  
Denis Barabé ◽  
Luc Brouillet ◽  
Charles Bertrand
Keyword(s):  
Key Words ◽  
Evolutionary History ◽  
Leaf Primordia ◽  
Mature Leaf ◽  
The Other ◽  
Leaf Morphogenesis ◽  
Angiosperm Phylogeny ◽  
The Family ◽  
History Of ◽  
Plesiomorphic State

The asymmetrical leaf of Begonia raises both biological and mathematical questions. The leaf organogenesis of two species of Begonia is analyzed in this study, one with asymmetrical, palmately nerved leaves, Begonia scabrida A.DC, the other with quasi-symmetrical, pinnately nerved leaves, Begonia radicans Vellozo. Additional observations on Begonia fagifolia Fischer, a species of the second type, are included for comparison. In the three species studied, the leaf primordia are asymmetrical at initiation, notwithstanding mature leaf symmetry or nervation. In B. radicans, the leaf is asymmetrical at initiation and becomes quasi-symmetrical, while in B. scabrida, it remains asymmetrical throughout. The Begonia leaf thus represents a true case of asymmetry, related to the morphogenetic properties of the vegetative apex. None of the present theories of leaf organogenesis are able to fully account for this phenomenon. Leaf asymmetry represents an ontogenetic constraint in the evolutionary history of Begoniaceae. The hypothesis is presented that the palmately nerved leaf is a plesiomorphic state and the pinnately nerved leaf an apomorphic one that appeared repeatedly within the family. Key words: Begoniaceae, leaf, morphogenesis, angiosperm, phylogeny, apex.

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