Hybrid origin of a cichlid population in Lake Malawi: implications for genetic variation and species diversity

Red spruce, Picearubens Sarg., from 30 provenances was tested over a 23-year period at six locations in the Maritimes Region of Canada. Twenty-eight of the provenances were from the Maritimes Region and two were from West Virginia. Hybrid index was used to distinguish pure red spruce from red–black spruce derivatives. Trees from three of the Maritimes provenances were considered to be of hybrid origin. These three provenances produced the fastest-growing trees in the tests. The genetic variation pattern, at the provenance level, in pure red spruce of Maritimes origin is not well defined. Use of seed from provenances identified as superior for reforestation would result in about 10% greater height and diameter growth than would be obtained from average seed. The use of seed of poor provenances could result in a corresponding loss of growth. Height at ages 10, 15, and 23 years and diameter at age 23 years were all strongly correlated, suggesting that superior provenances of red spruce can be identified at age 10. The Maritimes Region can be considered as a single breeding zone for tree improvement efforts with red spruce.

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Genetic variation of Taeniolethrinops praeorbitalis (Chisawasawa) in the central and southern Lake Malawi

UNISWA Journal of Agriculture ◽

10.4314/uniswa.v10i1.4605 ◽

2004 ◽

Vol 10 (1) ◽

Author(s):

Wisdom Changadeya ◽

Aggrey J.D. Ambali ◽

Lawrence B. Malekano

Keyword(s):

Genetic Variation ◽

Lake Malawi

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Relationship Between Genetic Variation and Diversity of Tree Species in Tropical Forests in the El Ocote Biosphere Reserve, Chiapas, Mexico

Tropical Conservation Science ◽

10.1177/1940082920978143 ◽

2021 ◽

Vol 14 ◽

pp. 194008292097814

Author(s):

Bárbara Cruz-Salazar ◽

Lorena Ruiz-Montoya ◽

Neptalí Ramírez-Marcial ◽

Maricela García-Bautista

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Species Diversity ◽

Tree Species ◽

Haplotype Diversity ◽

Biosphere Reserve ◽

Genetic Distances ◽

Community Diversity ◽

Environmental Selection ◽

Tree Communities

Knowledge of the genetic diversity of species in a biological community is useful for assessing the ecological and evolutionary processes that define the structure and dynamics of that community. We investigated the potential relationship between the trans-specific genetic diversity (or genetic diversity across tree species) and the diversity of tree species in a tropical subdeciduous forest. The nucleotide variation of the concatenated regions ITS 1 and ITS 3 (ITS1-3) was used to determine the trans-specific genetic diversity of 19 species of trees in five local communities at El Ocote Biosphere Reserve (REBISO), Chiapas, Mexico. Tree diversity was obtained by counting individual trees within 0.1 ha circular plots in each locality. The relationship between trans-specific genetic diversity and species diversity was established through simple linear regressions between genetic diversity parameters and community diversity. A correlation matrix was built with genetic distances (Kimura’s two-parameter model) and differences in species diversity between communities. A significant relationship was observed between nucleotide diversity (π) and species richness ( Sp), and a negative association between haplotype diversity and gamma diversity (γ). Our results show species-rich and genetically diverse tree communities and a weak association between trans-specific genetic variation and species diversity in tree communities at REBISO. This research suggests a possible ecological and genetic relationship within each community. Genetic diversity values may provide an important degree of variation upon which environmental selection pressures could operate, which may be helpful to face the current environmental modifications associated with climatic change.

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Species Diversity and Intraspecific Genetic Variation of Reticulitermes (Isoptera: Rhinotermitidae) Subterranean Termites in Woodland and Urban Environments of Missouri

Annals of the Entomological Society of America ◽

10.1603/008.102.0513 ◽

2009 ◽

Vol 102 (5) ◽

pp. 868-880 ◽

Cited By ~ 2

Author(s):

Olga P. Pinzon ◽

Richard M. Houseman

Keyword(s):

Genetic Variation ◽

Species Diversity ◽

Urban Environments ◽

Subterranean Termites ◽

Intraspecific Genetic Variation

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From Dampier to DNA: the 300-year-old mystery of the identity and proposed allopolyploid origin of Conostylis stylidioides (Haemodoraceae)

Australian Journal of Botany ◽

10.1071/bt00072 ◽

2001 ◽

Vol 49 (5) ◽

pp. 611 ◽

Cited By ~ 7

Author(s):

Siegfried L. Krauss ◽

Stephen D. Hopper

Keyword(s):

Genetic Variation ◽

Maximum Parsimony ◽

Hybrid Origin ◽

Maximum Parsimony Tree ◽

Aflp Data ◽

Parsimony Tree ◽

Different Populations ◽

Current Species ◽

Origin Hypothesis ◽

Hybridisation Event

The tetraploid Conostylis stylidioides (n= 16) has been proposed to be a stabilised hybrid between the diploid (n = 8) species C. prolifera and C. candicans because of morphological and geographical intermediacy, as well as a polyploid chromosome number. To test this hybrid-origin hypothesis, we used the DNA-fingerprinting technique amplified fragment length polymorphism (AFLP) and measured genetic variation within these taxa, as well as the putative outgroups C. robusta and C. aculeata. One AFLP primer pair generated 192 dominant markers for 36 samples from these species, of which 189 were polymorphic. Polymorphism within populations was uniformly high for all species, with 66–86% of all fragments polymorphic and estimates of heterozygosity ranging from 0.36 to 0.41. Ordination, UPGMA and maximum parsimony analyses of these genetic data consistently clustered species, supporting the current species’ level taxonomy. The intermediate placement of C. stylidioides between C. proliferaand C. candicans on the maximum parsimony tree supports the hybrid-origin hypothesis, although other interpretations are possible. The phenetic results for AFLP data, in which C. stylidioides is not strictly intermediate between C. prolifera and C. candicans, are either concordant with recent research suggesting that rapid intra- and inter-genomic rearrangements occur with the origin of polyploid taxa, or indicate an ancient hybridisation event. While our results do not reject the hybrid origin hypothesis, the extremely high levels of genetic variation detected with AFLP within these populations, in combination with extensive genomic reorganisation with the origin of C. stylidioides and the possibility of independent origins for different populations, make it difficult to confidently exclude other scenarios.

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Temporal Changes and Spatial Determinants of Plant Species Diversity and Genetic Variation

Long-Term Ecological Research ◽

10.1007/978-90-481-8782-9_20 ◽

2010 ◽

pp. 279-297 ◽

Cited By ~ 7

Author(s):

Cornelia Baessler ◽

Stefan Klotz ◽

Walter Durka

Keyword(s):

Genetic Variation ◽

Species Diversity ◽

Plant Species ◽

Temporal Changes ◽

Plant Species Diversity

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Different Sources of Allelic Variation Drove Repeated Color Pattern Divergence in Cichlid Fishes

Molecular Biology and Evolution ◽

10.1093/molbev/msaa237 ◽

2020 ◽

Author(s):

Sabine Urban ◽

Alexander Nater ◽

Axel Meyer ◽

Claudius F Kratochwil

Keyword(s):

Genetic Variation ◽

De Novo ◽

Allelic Variation ◽

Lake Victoria ◽

Cichlid Fish ◽

Lake Malawi ◽

Color Pattern ◽

Species Flock ◽

De Novo Mutations ◽

Phenotypic Divergence

Abstract The adaptive radiations of East African cichlid fish in the Great Lakes Victoria, Malawi, and Tanganyika are well known for their diversity and repeatedly evolved phenotypes. Convergent evolution of melanic horizontal stripes has been linked to a single locus harboring the gene agouti-related peptide 2 (agrp2). However, where and when the causal variants underlying this trait evolved and how they drove phenotypic divergence remained unknown. To test the alternative hypotheses of standing genetic variation versus de novo mutations (independently originating in each radiation), we searched for shared signals of genomic divergence at the agrp2 locus. Although we discovered similar signatures of differentiation at the locus level, the haplotypes associated with stripe patterns are surprisingly different. In Lake Malawi, the highest associated alleles are located within and close to the 5′ untranslated region of agrp2 and likely evolved through recent de novo mutations. In the younger Lake Victoria radiation, stripes are associated with two intronic regions overlapping with a previously reported cis-regulatory interval. The origin of these segregating haplotypes predates the Lake Victoria radiation because they are also found in more basal riverine and Lake Kivu species. This suggests that both segregating haplotypes were present as standing genetic variation at the onset of the Lake Victoria adaptive radiation with its more than 500 species and drove phenotypic divergence within the species flock. Therefore, both new (Lake Malawi) and ancient (Lake Victoria) allelic variation at the same locus fueled rapid and convergent phenotypic evolution.

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Genetic variation in a tropical tree species influences the associated epiphytic plant and invertebrate communities in a complex forest ecosystem

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2010.0183 ◽

2011 ◽

Vol 366 (1569) ◽

pp. 1329-1336 ◽

Cited By ~ 54

Author(s):

Sharon E. Zytynska ◽

Michael F. Fay ◽

David Penney ◽

Richard F. Preziosi

Keyword(s):

Genetic Variation ◽

Species Diversity ◽

Tree Species ◽

Positive Association ◽

Ecological Communities ◽

Significant Positive Association ◽

Invertebrate Communities ◽

Single Tree ◽

Epiphytic Plant ◽

The Impact

Genetic differences among tree species, their hybrids and within tree species are known to influence associated ecological communities and ecosystem processes in areas of limited species diversity. The extent to which this same phenomenon occurs based on genetic variation within a single tree species, in a diverse complex ecosystem such as a tropical forest, is unknown. The level of biodiversity and complexity of the ecosystem may reduce the impact of a single tree species on associated communities. We assessed the influence of within-species genetic variation in the tree Brosimum alicastrum (Moraceae) on associated epiphytic and invertebrate communities in a neotropical rainforest. We found a significant positive association between genetic distance of trees and community difference of the epiphytic plants growing on the tree, the invertebrates living among the leaf litter around the base of the tree, and the invertebrates found on the tree trunk. This means that the more genetically similar trees are host to more similar epiphyte and invertebrate communities. Our work has implications for whole ecosystem conservation management, since maintaining sufficient genetic diversity at the primary producer level will enhance species diversity of other plants and animals.

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