Isolation and characterization of microsatellite loci in tropical forage Stylosanthes capitata Vogel

Stylosanthes capitata is an important tropical pasture legume. Knowledge of genetic diversity and structure of S. capitata populations is of great importance for the conservation and germplasm management of this species. Thus, eight microsatellite markers were developed from an S. capitata-enriched library. They were characterized in 20 accessions from the germplasm collection of the Empresa Brasileira de Pesquisa Agropecuária (Embrapa). The observed and expected heterozygosities ranged from 0.16 to 0.85 and from 0.40 to 0.85, respectively. These microsatellites are the first set of molecular markers from this species and will contribute towards studies of genetic diversity, conservation and breeding of S. capitata.     

Genetic variation and population structure in desert bighorn sheep: implications for conservation

Bighorn sheep populations experienced a drastic reduction in both distribution and abundance until the advent of modern wildlife management, where improving viability of extant populations and translocating animals into historical habitat range have been the most important management policies. The fact that subspecies relationships among bighorn are ambiguous,together with the importance of selecting appropriate source stock and the expense of translocation projects, makes an understanding of subspecies relationships and genetic variation, within and between populations, important for the management and conservation of this species. In this study, genetic variation in 279 bighorn sheep from 13 study sites in Arizona, California, New Mexico and Alberta, Canada were examined by analyzing ten microsatellite loci to determine interpopulation differentiation and relationships between closely related taxa. All populations contained a substantial amount of genetic variation. Genetic differences between populations were large and roughly proportional to geographic distance. The significance of this to desert subspecies relationships and management is discussed.     

Phylogeography, hybridization and Pleistocene refugia of the kob antelope (Kobus kob)

Mitochondrial DNA control region sequences and seven microsatellites were used to estimate the genetic structuring, evolutionary history and historic migration patterns of the kob antelope (Kobus kob). Ten populations were analysed, representing the three recognized K. kob subspecies: K. k. kob in west Africa, K. k. thomasi in Uganda and K. k. leucotis in Sudan and Ethiopia. Despite being classified as K. k. thomasi and being phenotypically identical to the kob in Queen Elizabeth National Park (NP), the Murchison Falls population in Uganda showed high genetic similarity with the phenotypically distinct K. k. leucotis populations in Sudan and Ethiopia. This was regardless of marker type. Pairwise comparisons and genetic distances between populations grouped Murchison with K. k. leucotis, as did the Bayesian analysis, which failed to find any genetic structuring within the group. We propose that the divergent phenotype and life-history adaptations of K. k. leucotis reflect the isolation of kob populations in refugia in west and east Africa during the Pleistocene. Subsequent dispersal has led to secondary contact and hybridization in northern Uganda between lineages, which was supported by high levels of genetic diversity in Murchison. The reduced variability observed in Queen Elizabeth NP reflects a small founder population from west Africa and in part the decimation of Uganda's wildlife during the country's political turmoil in the 1970s. Due to similarities in phenotype and ecology, and the joint evolutionary history of their mtDNA sequences, the taxonomic status of K. k. kob and K. k. thomasi as separate subspecies is called into question.     

Characterization of 12 polymorphic microsatellite markers for Georgia false indigo (Amorpha georgiana Wilbur var. georgiana), an endangered species, and their utility in other dwarf Amorpha L. species

In order to facilitate the addition of a genetic component to conservation management plans for Georgia false indigo (Amorpha georgiana var. georgiana), a rare legume of the southeastern USA, 12 polymorphic microsatellite markers were developed. No gametic disequilibrium was detected among locus pairs, but observations for five of the loci significantly deviated from expected Hardy-Weinberg proportions. Cross-species testing was successful and demonstrated the utility of the majority of the markers in congeners Amorpha georgiana var. confusa and Amorpha herbacea. The results also suggested that A. georgiana var. confusa is tetraploid rather than diploid.     

Isolation of polymorphic microsatellite markers in the sub‐Saharan tree,Acacia (Senegalia) mellifera (Fabaceae: Mimosoideae)

We isolated 11 polymorphic microsatellite markers from Acacia mellifera, a savannah woodland tree in sub‐Saharan Africa and southern Arabia. The loci were screened for polymorphism using 48 Kenyan individuals. Allelic diversity ranged from three to 19 per locus and the polymorphic information content varied from 0.287 to 0.893. These loci will be useful in studies of genetic structure, gene flow and breeding systems.     

Floral development in Tribe Detarieae (Leguminosae: Caesalpinioideae): Amherstia, Brownea, and Tamarindus

Floral development was compared among three taxa in caesalpinioid tribe Detarieae sensu lato: Amherstia nobilis and Tamarindus indica have racemose, helically arranged inflorescences, while Brownea latifolia has cauliflorous capitate flower clusters that arise as racemes. All have acropetal flower order; initiation and development are sequential in all except Brownea, which is synchronous. All have paired persistent showy bracteoles. Floral symmetry is dorsiventral (zygomorphic) in all except Brownea, with radial symmetry at anthesis. Sepals initiate helically on a circular floral apex, starting with a median abaxial sepal, in all. Petals are initiated helically in Brownea, and unidirectionally in Amherstia and Tamarindus. Stamens are initiated unidirectionally in each stamen whorl in all except Amherstia, in which the outer whorl is bidirectional. The carpel initiates concurrently with the petals in Brownea, and with the outer stamens in the other taxa. The two upper (adaxial) sepal primordia become fused during development in all, so that the calyx appears tetramerous. Some reduced petals occur in Amherstia and Tamarindus, and some reduced stamens occur in all. All produce a hypanthium by zonal growth, and all except Tamarindus have the gynoecium attached adaxially to the hypanthial rim.     

New aspects in floral development of Papilionoideae: initiated but suppressed bracteoles and variable initiation of sepals

BACKGROUND AND AIMS: The increase of molecular data and the resulting insights into legume systematics make the search for new morphological characters and a careful re-investigation of already stated characters necessary. Bracteoles are small, reduced leaves borne close to the base of lateral branches. Although they seem unimportant in older buds, they have an ecological function in protecting the sepal primordia. Furthermore, a morphogenetic function in mediating the onset of sepal initiation is suspected in the literature. The occurrence of bracteoles varies within Papilionoideae, and their distribution is used in legume systematics. But this is open to criticism, because there is a tendency to use 'absent' for 'caducous'. Thus attention here was paid to the initiation of bracteoles as well as to the sequence of sepal initiation. METHODS: The floral development of 30 taxa out of 15 tribes of Papilionoideae was investigated using scanning electron microscopy (SEM). KEY RESULTS: In five taxa the bracteoles initiated, but suppressed early. Furthermore, a broad variability of sepal initiation was found. Besides the widely stated unidirectional pattern, modified unidirectionality, tendencies towards whorled, fully whorled, bidirectional and successive initiation of sepals were all found. CONCLUSION: Initiated but suppressed bracteoles are presented as a 'new' character in Papilionoideae. Considering the presence of bracteoles as a plesiomorphy, their suppression can be seen as a step towards completely reduced bracteoles. The remarkable variability of the sequence of sepal initiation questions the widely stated unidirectionality of organ initiation in Papilionoideae. The different modes of sepal initiation are deducible from the helical pattern of some caesalpinioids, which is seen as a developmental link of the flowers of Papilionoideae and Caesalpinioideae. The bidirectional sepal initiation is possibly a consequence of the morphogenetic function of bracteoles, although bidirectionality is not found in all taxa with reduced bracteoles.     

Cotyledon venation patterns in the Leguminosae: Mimosoideae

Cotyledon venation patterns are described for 131 species representing the four main tribes of the Mimosoideae. The range of variation in venation pattern falls within that described previously for the Caesalpinioideae and is consistent with the proposal that all patterns in the Leguminosae have been derived from a prototype with four vascular strands and a protoxylem trace in the petiole and seven primary veins in the lamina. Each tribe is characterized by a particular set of patterns, pattern frequencies and evolutionary trends. In the Mimoseae, correlations between venation pattern and cotyledon size and anatomy match those found in the Caesalpinioideae, but different correlations unique to these tribes occur in the Acacieae and Ingeae.