Fine-scale genetic structure among genetic individuals of the clone-forming monotypic genus Echinosophora koreensis (Fabaceae)

• Background and Aims For rare endemics or endangered plantspecies that reproduce both sexually and vegetatively it iscritical to understand the extent of clonality because assessmentof clonal extent and distribution has important ecological andevolutionary consequences with conservation implications. Asurvey was undertaken to understand clonal effects on fine-scalegenetic structure (FSGS) in two populations (one from a disturbedand the other from an undisturbed locality) of Echinosophorakoreensis, an endangered small shrub belonging to a monotypicgenus in central Korea that reproduces both sexually and vegetativelyvia rhizomes. • Methods Using inter-simple sequence repeats (ISSRs) asgenetic markers, the spatial distribution of individuals wasevaluated using Ripley's L(d)-statistics and quantified thespatial scale of clonal spread and spatial distribution of ISSRgenotypes using spatial autocorrelation analysis techniques(join-count statistics and kinship coefficient, F_ij) for totalsamples and samples excluding clones. • Key Results A high degree of differentiation betweenpopulations was observed (_ST(g) = 0·184, P < 0·001).Ripley's L(d)-statistics revealed a near random distributionof individuals in a disturbed population, whereas significantaggregation of individuals was found in an undisturbed site.The join-count statistics revealed that most clones significantlyaggregate at 6-m interplant distance. The Sp statistic reflectingpatterns of correlograms revealed a strong pattern of FSGS forall four data sets (Sp = 0·072–0·154), butthese patterns were not significantly different from each other.At small interplant distances (2 m), however, jackknifed 95% CIs revealed that the total samples exhibited significantlyhigher F_ij values than the same samples excluding clones. • Conclusion The strong FSGS from genets is consistentwith two biological and ecological traits of E. koreensis: bee-pollinationand limited seed dispersal. Furthermore, potential clone matesover repeated generations would contribute to the observed highF_ij values among genets at short distance. To ensure long-termex situ genetic variability of the endangered E. koreensis,individuals located at distances of 10–12 m should becollected across entire populations of E. koreensis.     

Detection of genetic variation among single-spore isolates and identification of genets ofArmillaria ostoyae by AFLP analysis with Texas RedTM-labeled selective primer

AFLP (amplified fragment length polymorphism) analysis was applied toArmillaria ostoyae isolates (single-spore isolates and field isolates from the same forest). For detection of AFLP, we have developed a modified method using DNA sequencer with Texas Red-labeled selective primer. In analysis of single-spore isolates, this technique provided large numbers of highly polymorphic DNA markers, which can be used to identify genets. The results suggested that outbreeding might be common inA. ostoyae.     

Patterns of cryptic hybridization revealed using an integrative approach: a case study on genets (Carnivora, Viverridae, Genetta spp.) from the southern African subregion

Recent years have seen the development of molecular‐based methodologies to investigate hybridization and its impact on the evolutionary process. However, morphological characterization of hybrid zones has only scantily been considered, especially in zootaxa. Thus, the level of congruence between molecular and morphological characters when attempting to detect hybrids remains a poorly tackled area. The genets (genus Genetta) provide an ideal case study for further investigation of the respective contribution of morphology and DNA in hybrid zone characterization because (1) their morphology has recently been exhaustively explored and (2) the existence of hybrid zones in southern Africa was proposed in the literature. We assessed levels of hybridization among the southern African genets, and questioned the role of ecological factors on the hybridization patterns detected. We used an integrative approach involving nine discrete morphological characters and a diagnostic discriminant function, geometric morphometrics and sequences of cytochrome b including collection specimens. The combination of independent materials allowed us to accurately reassess the level of hybridization in southern African genets, and revealed cryptic, interspecific gene flows. Morphology unambiguously detected a low number of G. maculata × G. tigrina hybrids and rejected the hypothesis of a large intergradation zone in KwaZulu‐Natal, thus supporting the species status of the two genets. Cytochrome b analyses revealed: (1) cryptic, massive hybridization between G. tigrina and the sympatric G. felina, and (2) a trace of reticulation (one sequence) between G. tigrina and the allopatric G. genetta. The type specimen of G. mossambica Matschie, 1902 is considered to be a morphological hybrid between G. maculata and G. angolensis. Remarkably, the morphological approaches (discrete characters and morphometrics) proved complementary to conclusions derived from cytochrome b sequences. Whilst morphometrics was generally unable to accurately identify all putative hybrids, this approach revealed diagnostic cranial shape differences between recognized species as well as the cryptic G. ‘letabae’ (included in the super‐species G. maculata). Morphometrics also confirmed the diagnostic value and age dependency of discrete characters. Our integrative approach appeared necessary to the detection of cryptic hybridizations and to the comprehensive characterization of hybrid zones. The recurrent detection of hybrids exhibiting tigrina‐like coat patterns may suggest (1) asymmetric hybridization of G. tigrina males to females of other species and (2) positive selection for tigrina‐like phenotype in South African habitats, but these hypotheses will have to be further tested using other sources of evidence. Despite the precise mosaic of hybrid zones identified in southern African genets, the environmental factors that shape patterns of distribution of hybrids remain unclear. Nevertheless, in the light of our range reassessment, it appears that seasonality of precipitation and periods of annual frost may play stringent roles in the distribution of genets. The complementarity of our results based on morphology and molecules is regarded as encouraging for the further development of integrative approaches in order to better understand the complex phenomena that underlie hybridization processes. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 11–33.     

Spatial genotypical diversity of <Emphasis Type="Italic">Sesleria albicans</Emphasis> (Poaceae) in a dry grassland community

Spatial genotypical diversity of Sesleria albicans Kit. ex Schultes was studied in a dry grassland community by isozyme analysis. The aim was to identify the genetical individuals within the studied population and to assess the species’ clonal growth parameters. Vegetative mobility and branching intensity were measured in field for the sake of the correct interpretation of the results. Five isozyme systems were analyzed and interpreted (MDH, MNR, 6-PGDH, SkDH, LAP). Altogether, 98 distinct isozyme profiles were identified within an area of 2 m². Average genotype identity rapidly decreased with distance. Several very remote ramets (more than 1 m) belonging to the same genet were identified. The longest distance between ramets of the same genotype was 153 cm. With average annual rhizome increment of 13.59 mm assessed for the studied population the age of genet with the most remote ramets exceeded 56 years by a bi-directional growth and 112 years by a growth in single direction. Number of daughter tillers produced by a tiller per year was 0.67 (branching intensity, median) and the median of tiller life span was 2.5 years. The high genotypical diversity of S. albicans in the studied population could be a result of both, regular and continuous seed production with subsequent seedling recruitment and long life span of genets.     

Fission and the dynamics of genets and ramets in clonal cnidarian populations

Until relatively recently many species of entomostracan crustaceans were thought to have widespread, even cosmopolitan distributions. Evidence now suggests that this is far less the case than thought. However, an exception appears to be provided by the crustaceans of episodically filled waterbodies. Typically these include Anostraca, Notostraca and Conchostraca. The paper considers the distribution of Triops australiensis (Branchiopoda: Notostraca) in Australia. There, it is a frequent inhabitant of episodically filled temporary waters. It is absent from such waters in northern Australia. A biogeoclimatic analysis using the program BIOCLIM indicates that this is because of the absence of suitable localities. BIOCLIM enables the preparation of maps which provide statistical predictions of climates suitable for the survival of a particular taxon. These predictions are based upon the known climate of localities where the taxon in question actually occurs. It is suggested that for the biota of shallow ephemeral waters (such as those typically inhabited by Anostraca, Conchostraca and Notostraca) biogeoclimatic analysis has a powerful predictive value.