Mating and Parental Care in Lake Tanganyika's Cichlids

Cichlid fishes of Lake Tanganyika display a variety of mating and parental care behaviors, including polygamous and monogamous mouthbrooding and substrate breeding, cooperative breeding, as well as various alternative reproductive tactics such as sneaking and piracy. Moreover, reproductive behaviors sometimes vary within species both in space and in time. Here, I survey reports on mating and parenting behaviors of Lake Tanganyika cichlid species and address the evolution of mating and parental care patterns and sexual dimorphism. Notes on measures of sexual selection intensity and the difficulties of defining mating systems and estimating selection intensities at species level conclude the essay

Embryogenesis in microspore culture of Vitis subspecies

Embryoid structures showing epidermal layers have been regenerated from isolated Vitis microspores. Experiments were carried out on 8 genotypes of Vitis including different donor plant growth conditions, chilling of microspores (4 °C), heat shock (35 °C) and colchicine exposure (10, 25 and 50 mg/l) as induction treatments and incubation of the cultures on 87 different solid and liquid NN and LS media. The reactions of the cultured microspores included enlargement and thickening of the exine, formation of microcalli, calli, globular proembryos and embryoid structures displaying cell differentiation. Callus formation took place mainly on solid LS media with 3 % or 12 % sucrose, whereas most of the embryoids developed on NN media with 3 % sucrose. Both, callus and embryoid formation, were promoted by colchicine treatment. 8 months after transfer of calli and embryoids to subculture media, 4 embryoids still showed cell proliferation

Genotyping of grapevine and rootstock cultivars using microsatellite markers

Sixty-six grapevine and rootstock cultivars from an Austrian germplasm collection were genotyped using the following 10 microsatellite loci: VVS1, VVS2, VVS3, VVS4 (THOMAS and SCOTT 1993), VVS29 (THOMAS, pers. comm.), VVMD5, VVMD7 (BOWERS et al. 1996), VVMD28, VVMD32 and VVMD36 (BOWERS and MEREDITH, pers, comm.). All cultivars except those which are thought to be closely related (e.g. Portugieser blau and Portugieser grun) provided unique allelic profiles. A phenogram based on pairwise similarity values revealed the separation of rootstock cultivars from the Vitis vinifera varieties. The probability for the presence of null alleles was estimated from heterozygote deficiencies and null alleles were statistically excluded at 9 of the 10 loci. In order to demonstrate the distinctive power of the microsatellite markers investigated, gene diversity (GD) values were calculated. For both grapevine and rootstock cultivars we estimated a GD range from 0.70 to 0.91, while GD values for grapevines only range from 0.52 to 0.87 and values for rootstocks from 0.29 to 0.86

Genetic continuity of brood-parasitic indigobird species

Speciation in brood-parasitic indigobirds (genus Vidua ) is a consequence of behavioural imprinting in both males and females. Mimicry of host song by males and host fidelity in female egg laying result in reproductive isolation of indigobirds associated with a given host species. Colonization of new hosts and subsequent speciation require that females occasionally lay eggs in the nests of novel hosts but the same behaviour may lead to hybridization when females parasitize hosts already associated with other indigobird species. Thus, retained ancestral polymorphism and ongoing hybridization are two alternative explanations for the limited genetic differentiation among indigobird species. We tested for genetic continuity of indigobird species using mitochondrial sequences and nuclear microsatellite data. Within West Africa and southern Africa, allopatric populations of the same species are generally more similar to each other than to sympatric populations of different species. Likewise, a larger proportion of genetic variation is explained by differences between species than by differences between locations in alternative hierarchical amovas, suggesting that the rate of hybridization is not high enough to homogenize sympatric populations of different species or prevent genetic differentiation between species. Broad sharing of genetic polymorphisms among species, however, suggests that some indigobird species trace to multiple host colonization events in space and time, each contributing to the formation of a single interbreeding population bound together by songs acquired from the host species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75693/1/j.1365-294X.2005.02492.x.pd

Nuclear and mitochondrial data reveal different evolutionary processes in the Lake Tanganyika cichlid genus Tropheus

<p>Abstract</p> <p>Background</p> <p>Cichlid fishes are notorious for their wealth of intra- and interspecific colour pattern diversity. In Lake Tanganyika, the endemic genus <it>Tropheus </it>represents the most impressive example for geographic variation in the pattern and hue of integument colouration, but the taxonomy of the over 100 mostly allopatric colour morphs remains to a large degree unresolved. Previous studies of mitochondrial DNA sequence data revealed polyphyly of the six nominally described species and complex phylogeographic patterns influenced by lake level fluctuations and population admixture, and suggested the parallel evolution of similar colour patterns in divergent evolutionary lineages. A gene tree of a rapidly radiating group may be subject to incomplete and stochastic lineage sorting, and to overcome this problem we used multi-locus, nuclear AFLP data in comparison with mtDNA sequences to study diversification, migration and introgression in <it>Tropheus </it>colour morphs in Lake Tanganyika.</p> <p>Results</p> <p>Significant incongruence between phylogenetic reconstructions from mitochondrial and AFLP data suggested incomplete sorting of mitochondrial haplotypes as well as frequent introgression between differentiated lineages. In contrast to the mitochondrial phylogeny, the AFLP phenogram was largely congruent with species classifications, colour pattern similarities, and in many cases also with the current geographic distribution of populations, and did not produce evidence of convergent colour pattern evolution. Homoplasy in the AFLP data was used to identify populations that were strongly affected by introgression.</p> <p>Conclusion</p> <p>Different evolutionary processes were distinguished by the combination of mitochondrial and AFLP data. Mitochondrial phylogeographic patterns retained signals of large-scale migration events triggered by historical, major lake level fluctuations, whereas AFLP data indicated genetic cohesion among local groups of populations resulting from secondary contact of adjacent populations in the course of the more frequently occurring, minor lake level fluctuations. There was no support for the parallel evolution of similar colour patterns in the AFLP data. Genetic signatures of introgression and hybridisation detected in several populations suggest that lake level fluctuations drove the stunning diversification of <it>Tropheus </it>morphs not only through population fragmentation, but also by promoting hybridisation between differentiated morphs in secondary contact.</p

Evolutionary History of Lake Tanganyika's Predatory Deepwater Cichlids

Hybridization among littoral cichlid species in Lake Tanganyika was inferred in several molecular phylogenetic studies. The phenomenon is generally attributed to the lake level-induced shoreline and habitat changes. These allow for allopatric divergence of geographically fragmented populations alternating with locally restricted secondary contact and introgression between incompletely isolated taxa. In contrast, the deepwater habitat is characterized by weak geographic structure and a high potential for gene flow, which may explain the lower species richness of deepwater than littoral lineages. For the same reason, divergent deepwater lineages should have evolved strong intrinsic reproductive isolation already in the incipient stages of diversification, and, consequently, hybridization among established lineages should have been less frequent than in littoral lineages. We test this hypothesis in the endemic Lake Tanganyika deepwater cichlid tribe Bathybatini by comparing phylogenetic trees of Hemibates and Bathybates species obtained with nuclear multilocus AFLP data with a phylogeny based on mitochondrial sequences. Consistent with our hypothesis, largely congruent tree topologies and negative tests for introgression provided no evidence for introgressive hybridization between the deepwater taxa. Together, the nuclear and mitochondrial data established a well-supported phylogeny and suggested ecological segregation during speciation

Introgressive Hybridization between Color Morphs in a Population of Cichlid Fishes Twelve Years after Human-Induced Secondary Admixis

In the extremely species-rich haplochromine cichlid fishes of the East African Great Lakes, prezygotic isolation between closely related species is often maintained by color-assortative mating. In 1998, local fisherman working for the ornamental fish trade released different color morphs of the cichlid genus Tropheus into a small harbor basin in the southern part of Lake Tanganyika. This artificial amalgamation of color morphs provides a unique possibility to study mating patterns in cichlids in a natural environment over time. In a precursor study, we analyzed genotypes and phenotypes of almost 500 individuals sampled between 1999 and 2001 and uncovered a marked degree of color-assortative mating, which depended on the level of color pattern dissimilarity between morphs. Twelve years after introduction of nonindigenous morphs, we again sampled Tropheus individuals from the harbor basin and an adjacent, originally pure population and analyzed phenotypes (coloration) and genotypes (mitochondrial control region and 9 microsatellite loci) to assess the current status of the admixed population. Principal component analyses of color score data and population assignment tests demonstrate an increasing level of introgressive hybridization between morphs but also some ongoing color-assortative mating within morphs. The observed mating pattern might have been influenced by fluctuating environmental conditions such as periodic algal blooms or increased sedimentation causing turbid conditions in an otherwise clear lak

Preface: Advances in Cichlid Research V:Behavior, Ecology, and Evolutionary Biology

The current special issue is the fifth in a series of special issues published in Hydrobiologia exclusively devoted to cichlid fish research. The freshwater fish family Cichlidae accounts for approximately 10% of today’s teleost diversity and is naturally distributed from southern North America to southern South America, across most of Africa, to Madagascar and India. Their tremendous diversity in morphology, behavior, and ecology, as well as their astounding speciation rates and numerous species-rich adaptive radiations have enthralled biologists for decades (e.g., Boulenger, 1898; Kosswig, 1947; Fryer, 1960), such that cichlids are now among the prime model systems in evolutionary biology research (e.g., Salzburger, 2018). We are pleased to present a collection of 19 papers that investigate questions of taxonomy, biogeography, morphology, behavior, physiology, and parasitology. Many of the key ingredients of cichlid diversification are addressed by these studies, including mating, brood care and social interactions, color pattern, and body shape, as well as adaptations of the visual system and the trophic apparatus. Papers are summarized below in the order in which they appear in this special issue. We hope you enjoy reading the contributions

Application of microsatellite markers to parentage studies in grapevine

The use of microsatellites in genetic analysis does not only allow differentiation but also identification and parentage analysis of grapevine cultivars. Many of the cultivars which are of great economic importance, like Cabernet Sauvignon, have been selected and propagated centuries ago and often lack reliable documentation about their origins. In our study, 51 grapevine cultivars were genotyped at 24 microsatellite loci and searched for possible parent-offspring combinations. Our data confirm the origin of Cabernet Sauvignon from a cross between Cabernet franc and Sauvignon blanc. Furthermore we proved the parentage of the cultivars Neuburger (Silvaner x Veltliner rot), Blauburger (Portugieser blau x Blaufränkisch), Zweigelt (Blaufränkisch x St. Laurent) and Müller-Thurgau (Rheinriesling x Chasselas de Courtillier) at 24 SSR loci

Genetic characterization of Croatian grapevine cultivars and detection of synonymous cultivars in neighboring regions

Twenty-two native Croatian grapevine varieties representing three different growing and climatic regions (Dalmatia, Istria, continental Croatia) have been genotyped at nine SSR loci. The identical genotypes of the Croatian cultivars Plavina and Brajdica confirmed the hypothesis they are the same variety. Comparing the SSR profiles of the Croatian cultivars with the profiles stored in a database containing about 300 European cultivars, further three pairs of synonyms were revealed: Teran Bijeli shares its genotype with the Italian cultivar Prosecco, Muskat Ruza Porecki corresponds to cv. Rosenmuskateller from North Italy and Moslavac is identical to the Hungarian variety Furmint. The microsatellite-based definitions of these synonyms are strongly supported by ampelographic observations. The genetic variability within the investigated Croatian cultivars was high with a genetic diversity of 75 %. A dendrogram based on allele sharing distances reflected neither common morphological features nor common geographic origins of the cultivars