Phenological shifts and genetic differentiation between sympatric populations of Sargassum horneri (Fucales, Phaeophyceae) in Japan

2020 ◽  
Vol 642 ◽  
pp. 103-116
Author(s):  
Y Homma ◽  
S Okuda ◽  
M Kasahara ◽  
F Takahashi ◽  
S Yoshikawa ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Field Investigation ◽  
Sargassum Horneri ◽  
Hybrid Origin ◽  
Reproductive Phenology ◽  
The Sea Of Japan ◽  
Sympatric Populations ◽  
Seaweed Species ◽  
Bayesian Cluster ◽  
Phenological Shift

Marked seasonality, especially in sexual reproduction, is common among seaweed species along temperate coasts and increases the possibility of successful fertilization in outcrossing species. A phenological shift in reproductive seasons, therefore, could be an effective isolation barrier between conspecific seasonal populations, although its power has not been verified in algae. Sargassum horneri, a major component of seaweed beds along the temperate coast of Japan, is known for variability in its reproductive phenology. To understand the significance of phenological shift as an isolation barrier in seaweed species, phenological investigations of S. horneri seasonal populations on the Sea of Japan coast of central Honshu, Japan, were combined with Bayesian cluster analysis based on a nuclear simple sequence repeat genotype. Results from these analyses concordantly suggest a genetic differentiation between the seasonal populations, although almost 20% of field-collected plants were estimated to be hybrids or have a hybrid origin based on results of Bayesian cluster analyses using experimental hybrids. A collapse of seasonal isolation was also detected at the site of the field investigation, and a high percentage of putative hybrids in the following generation at the site (41%) suggested significant seasonal isolation in the differentiation observed in this study.

scholarly journals The identity of Erica flavisepala

Bothalia ◽  
1977 ◽  
Vol 12 (2) ◽  
pp. 195-197
Author(s):  
E. G. H. Oliver
Keyword(s):  
Morphological Characters ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Sympatric Populations

The recording of a few scattered plants of  E. flavisepala Guth. Bol. among sympatric populations of two other species led to a comparison of their morphological characters. From this comparison a putative hybrid origin was indicated, thus  E. x  flavisepala Guth. Bol.=E.  thunbergii Montin  X  E. sphaerocephala Wendl.

scholarly journals Reciprocal hybridization between diploid Ficaria calthifolia and tetraploid Ficaria verna subsp. verna: evidence from experimental crossing, genome size and molecular markers

2019 ◽  
Vol 189 (3) ◽  
pp. 293-310 ◽  
Author(s):  
Ondřej Popelka ◽  
Michal Sochor ◽  
Martin Duchoslav
Keyword(s):  
Genome Size ◽  
Morphological Variability ◽  
Plastid Dna ◽  
Genotypic Diversity ◽  
Hybrid Origin ◽  
Aflp Analysis ◽  
Sympatric Populations ◽  
Aflp Data ◽  
Evolutionary Forces ◽  
Genetic Clusters

Abstract Ficaria is a taxonomically intriguing polyploid complex with high morphological variability. Both hybridization and polyploidization have been suggested as the main evolutionary forces behind the high morphological variability in this genus; however, detailed studies are lacking. In Central Europe, two Ficaria taxa (diploid F. calthifolia and tetraploid F. verna subsp. verna) occasionally co-occur in local sympatry, which might result in hybridization. We investigated sympatric populations of the two Ficaria taxa using flow cytometry, chromosome counts, AFLP analysis and plastid DNA sequencing; we also performed experimental homoploid and heteroploid crosses to determine the frequency and direction of hybrid triploid formation, an alternative route of triploid origin (autopolyploidy) and the possibility of a one-step neoallotetraploid origin. Sympatric populations were composed of three genetic clusters corresponding to diploid F. calthifolia (2n = 16), tetraploid F. verna subsp. verna (2n = 32) and triploid plants (2n = 24). The holoploid genome size and AFLP data suggest a hybrid origin of the triploids, thereby making their formation via autopolyploidization in F. calthifolia unlikely. The triploid populations are monoclonal and of independent origin. In contrast, the parental populations exhibit high genotypic diversity and frequent sexual reproduction, including those of predominantly asexual F. verna subsp. verna. Experimental crossing confirmed that both parental taxa produce fertile seeds via a sexual pathway, but not by apomixis, and that both serve as pollen acceptors in heteroploid crosses, which is consistent with the plastid sequencing. However, hybridization is asymmetric, with maternal-excess crosses being significantly more successful. No signs of neoautotetraploidization or neoallotetraploidization were detected. In summary, recent gene flow between the studied Ficaria taxa is either limited or absent.

scholarly journals Genetic Structure of Colletotrichum gloeosporioides sensu lato Isolates Infecting Papaya Inferred by Multilocus ISSR Markers

2013 ◽  
Vol 103 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Sephra N. Rampersad
Keyword(s):  
Cluster Analysis ◽  
Genetic Differentiation ◽  
Colletotrichum Gloeosporioides ◽  
Gene Diversity ◽  
Polymorphic Loci ◽  
Bayesian Cluster Analysis ◽  
The Mean ◽  
Bayesian Cluster ◽  
Group 1 ◽  
Issr Primers

Colletotrichum gloeosporioides sensu lato is widely distributed throughout temperate and tropical regions and causes anthracnose disease in numerous plant species. Development of effective disease management strategies is dependent on, among other factors, an understanding of pathogen genetic diversity and population stratification at the intraspecific level. For 132 isolates of C. gloeosporioides sensu lato collected from papaya in Trinidad, inter-simple-sequence repeat-polymerase chain reaction (ISSR-PCR) generated 121 polymorphic loci from five ISSR primers selected from an initial screen of 22 ISSR primers. The mean percentage of polymorphic loci was 99.18%. Bayesian cluster analysis inferred three genetic subpopulations, where group 1 consisted exclusively of isolates collected in the southern part of Trinidad whereas groups 2 and 3, although genetically distinct, were mixtures of isolates collected from both the northern and southern parts of Trinidad. Principal coordinates analysis and unweighted pair-group method with arithmetic mean phylogeny were concordant with Bayesian cluster analysis and supported subdivision into the three subpopulations. Overall, the total mean gene diversity was 0.279, the mean within-population gene diversity was 0.2161, and genetic differentiation for the Trinidad population was 0.225. Regionally, northern isolates had a lower gene diversity compared with southern isolates. Nei's gene diversity was highest for group 1 (h = 0.231), followed by group 2 (h = 0.215) and group 3 (h = 0.202). Genotypic diversity was at or near maximum for all three subpopulations after clone correction. Pairwise estimates of differentiation indicated high and significant genetic differentiation among the inferred subpopulations (Weir's θ of 0.212 to 0.325). Pairwise comparisons among subpopulations suggested restricted gene flow between groups 1 and 2 and groups 1 and 3 but not between groups 2 and 3. The null hypothesis of random mating was rejected for all three inferred subpopulations. These results suggest that pathogen biology and epidemiology as well as certain evolutionary factors may play an important role in population substructuring of C. gloeosporioides sensu lato isolates infecting papaya in Trinidad.

scholarly journals Natural hybridization between two butterfly bushes in Tibet: dominance of F1 hybrids promotes strong reproductive isolation

2021 ◽  
Author(s):  
Rongli Liao ◽  
Weibang Sun ◽  
Yongpeng Ma
Keyword(s):  
Morphological Characters ◽  
Natural Hybridization ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Sympatric Populations ◽  
Intergenic Spacers ◽  
Typical Distribution ◽  
Hybridization Origin ◽  
Butterfly Bush ◽  
Disturbed Habitats

Abstract Background: It has been recognized that certain amount of habitat disturbance is a prerequisite for occurrence of natural hybridization, yet we are currently still not aware of any studies exploring hybridization and reproductive barriers to those plants preferably occupying disturbed habitats. Buddleja plants (also called butterfly bush) generally grow in disturbed habitat, and several species with hybrid origin only on basis of morphology evidence have been proposed. Results: In the present study, we test the natural hybridization origin hypothesis of B. × wardii in two sympatric populations of three taxa including B. × wardii and its parents (B. alternifolia and B. crispa) plus 4 referenced parental populations, using four nuclear genes and three chloroplast intergenic spacers, as well as with 10 morphological characters. Our results suggest that at both sites B. × wardii was likely to be hybrids between B. alternifolia and B. crispa, and moreover, most of the hybrids examined were confirmed to be F1s. This was further supported by morphology as no transgressive characters were detected. B. crispa was found to be the maternal parent in Bahe (BH) population from the cpDNA. While in the Taji (TJ) population was difficult to distinguish the hybridization direction due to the shared haplotypes of cpDNA between B. alternifolia and B. crispa, we still predicted the similar unidirectional hybridization pattern due to results from cross-specific pollination treatments which supported the “SI x SC rule”. Conclusions: Hybrids mainly consisting of F1s can successfully impede gene flow and thus maintain species boundaries of parental species in its typical distribution of Buddleja, i.e. disturbed habitats.

Genetic differentiation and introgression amongst Thylogale (pademelons) taxa in eastern Australia

2011 ◽  
Vol 59 (2) ◽  
pp. 103 ◽  
Author(s):  
M. D. B. Eldridge ◽  
K. Heckenberg ◽  
L. E. Neaves ◽  
C. J. Metcalfe ◽  
S. Hamilton ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Dispersal Ability ◽  
Sympatric Populations ◽  
Genetic Studies ◽  
Eastern Australia ◽  
Moist Forest ◽  
Phylogeographic History ◽  
History Of ◽  
Wet Tropics ◽  
Mtdna Markers

Although pademelons (Thylogale) are widespread and common in coastal eastern Australia, they have been largely neglected in population genetic studies. Here we use 10 microsatellite loci and the mitochondrial DNA (mtDNA) cytochrome b (Cytb) gene to examine genetic differentiation amongst populations of the red-necked (Thylogale thetis) and red-legged (T. stigmatica) pademelon in eastern Australia. Evidence of hybridisation was detected between subspecies of T. stigmatica in central Queensland. Specimens sampled between Eungella and Sarina were found to represent a broad (~90 km) zone of introgression, for both nuclear and mtDNA markers, between T. s. stigmatica (Wet Tropics) and T. s. wilcoxi (south-east Queensland). In addition, individuals sampled from around Proserpine were genetically T. s. stigmatica rather than T. s. wilcoxi, as had previously been assumed. This observation raises some intriguing questions about the dispersal ability of T. stigmatica and the phylogeographic history of moist forest taxa in eastern Australia. Only limited evidence of introgression was detected between sympatric populations of T. thetis and T. s. wilcoxi in south-east Queensland.

Myanmar mango landraces reveal genetic uniqueness over common cultivars from Florida, India, and Southeast Asia

Genome ◽  
2010 ◽  
Vol 53 (4) ◽  
pp. 321-330 ◽  
Author(s):  
R. Hirano ◽  
Than Htun Oo ◽  
K. N. Watanabe
Keyword(s):  
Genetic Differentiation ◽  
Southeast Asia ◽  
Genetic Background ◽  
Mangifera Indica ◽  
Neighbor Joining ◽  
Large Area ◽  
Principal Coordinates ◽  
Low Degree ◽  
Bayesian Cluster ◽  
Private Alleles

Mango ( Mangifera indica ) is believed to have evolved in a large area spanning northeastern India, Bangladesh, and northwestern Myanmar. We compared the genetic structure of mango accessions from Myanmar with that of mango accessions from Florida, India, and Southeast Asia with 11 SSR markers. The Myanmar accessions exhibited considerable genetic diversity (unbiased heterozygosity, UHe = 0.698) and a high number of private alleles. Despite the low degree of genetic differentiation among accessions (global Fst, θ = 0.123), Myanmar’s accessions were distinguishable from mango accessions from Florida, India, and Southeast Asia in a principal coordinates plot. Genetic differentiation of the Myanmar accessions from other groups was also observed in a Bayesian cluster analysis. No population structure among Myanmar accessions was revealed by a neighbor-joining tree. Our results revealed a broad genetic background and genetic distinctiveness of mango in Myanmar. We discuss the implications for diversification mechanisms based on the embryo type characteristics and provide recommendations for conservation efforts.

Biochemical and Morphological Evidence for a New Species of River Crab Potamonautes Parvispina Sp. Nov. (Brachyura, Potamonautidae)

Crustaceana ◽  
1997 ◽  
Vol 70 (6) ◽  
pp. 737-753 ◽  
Author(s):  
Barbara A. Stewart
Keyword(s):  
South Africa ◽  
New Species ◽  
Genetic Differentiation ◽  
Morphological Evidence ◽  
Western Cape ◽  
Sympatric Populations ◽  
Olifants River ◽  
Allozyme Loci ◽  
A New Species

AbstractPotamonautid river crabs were collected from four sites along the Olifants River in the Western Cape, South Africa in order to determine morphological and genetic differentiation among these populations. Two distinct forms were identified, and fixed allele differences at some allozyme loci between sympatric populations of the two forms confirmed that they were reproductively isolated. It was concluded that these forms represent two species, one of which was previously unknown, and is described in this paper as Potamonautes parvispina sp. nov.

Low Genic Variation between Black Ducks and Mallards

The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 701-709 ◽  
Author(s):  
C. Davison Ankney ◽  
Darrell G. Dennis ◽  
Lisa N. Wishard ◽  
James E. Seeb
Keyword(s):  
Genetic Differentiation ◽  
Genetic Data ◽  
Genetic Distances ◽  
Allozyme Electrophoresis ◽  
Sympatric Populations ◽  
Black Duck ◽  
Genic Variation ◽  
American Black ◽  
The Mean ◽  
East West

Abstract We used allozyme electrophoresis to estimate the degree of genetic differentiation among allopatric and sympatric populations of American Black Ducks (Anas rubripes) and Mallards (A. platyrhynchos). Mallards were collected in California, Saskatchewan, Manitoba, and Ontario, and Black Ducks were collected in Newfoundland, Nova Scotia, and Ontario. The mean genetic distances, D̄, between Black Duck populations (0.0007), between Mallard populations (0.0010), and between Mallard and Black Duck populations (0.0006) were virtually identical; there was as much genetic differentiation within the two species as there was between them. Such small genetic distances are characteristic of local populations of avian species in other orders, and are consistent with what is known about the lack of reproductive isolation between Black Ducks and Mallards. Although the two taxa are still somewhat split on an east-west basis, our genetic data do not support even subspecific status for the Black Duck.

The identity of Erica vinacea and notes on hybridization in Erica

Bothalia ◽  
1986 ◽  
Vol 16 (1) ◽  
pp. 35-38 ◽  
Author(s):  
E. G. H. Oliver
Keyword(s):  
Morphological Characters ◽  
Hybrid Origin ◽  
Putative Hybrid ◽  
Sympatric Populations

The rediscovery of Erica vinacea L. Bol. among sympatric populations of two other species led to a comparison of their morphological characters. Results of this study indicate a putative hybrid origin: E. x  vinacea L. Bol. = E. fastigiata L. x  E. fervida L. Bol.

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