Evidence of facultative parthenogenesis in three Neotropical pitviper species of the Bothrops atrox group

We examined four suspected cases of facultative parthenogenesis in three species of a neotropical lineage of pitvipers of the Bothrops atrox group. Reproduction without mating was observed in captive females of B. atrox, B. moojeni and B. leucurus housed alone for seven years (the two former species) and nine years (the latter one). In addition to the observation of captivity data, we investigated molecularly this phenomenon using heterologous microsatellites. DNA was extracted from the mothers’ scales or liver, from embryo and newborn fragments, and yolked ova. Four of the microsatellites showed good amplification using Polymerase Chain Reaction and informative band segregation patterns among each mother and respective offspring. Captivity information, litter characteristics (comparison of the number of newborns, embryos and yolked ova) and molecular data altogether agreed with facultative parthenogenesis predictions in at least three out of the four mothers studied: B. atrox (ID#933) was heterozygous for three out of the four markers, and the sons S1 and S2 were homozygous; B. moojeni (BUT86) was heterozygous for two out of four markers, offspring S1, S3, E2, and E4, and O1 to O6 were homozygous; and B. leucurus (MJJS503) was heterozygous for three out of four markers, and son E1 and O1 were homozygous. B. moojeni (BUT44) was homozygous for all loci analyzed in the mother and offspring, which although not informative is also consistent with parthenogenesis. This study represents the first molecular confirmation of different pitviper species undergoing facultative parthenogenesis among Neotropical endemic snakes.

Genetic diversity of sorghum (Sorghum bicolor (L) Moench) accessions from thirteen regions of Burkina Faso

Sorghum (Sorghum bicolor (L.) Moench) is a staple food crop for West African countries in general and Burkina Faso in particular. It is mainly grown by small holder farmers for their livelihoods. They grow their landraces which is a mixture of more than two varieties. Unfortunately, the yields of farmer varieties are low compared to improved ones bred by sorghum breeders with the potential up to 3t/ha. The objective of the study was to identify the genetic diversity between improved varieties released by research institutions and farmer accessions at the molecular level. DNA sample were collected from hundred and twenty-three accessions collected from thirteen regions of Burkina Faso. DNA samples were successfully genotyped using a multiplexed complex of 28 microsatellites DNA markers for 110 genotypes. The sorghum genotypes comprised of Guinea, Caudatum and Guinea-Caudatum races. Farmer varieties were defined mainly in Guinea and Guinea-Caudatum races while the improved varieties were mainly Caudatum races. The inbreeding level FIS (the inbreeding level within a given population) for each group improved, farmer varieties varied between -1 <FIS>1. This shows the autogenous nature of sorghum varieties. Breeding schemes can therefore be designed for improvement of farmer preferred varieties.Keywords: Sorghum Microsatellites, Guinea, Caudatum, Yield, Landraces

Mediterranean swordfish (Xiphias gladius Linnaeus, 1758) population structure revealed by microsatellite DNA: genetic diversity masked by population mixing in shared areas

Background The Mediterranean swordfish stock is overfished and considered not correctly managed. Elucidating the patterns of the Mediterranean swordfish population structure constitutes an essential prerequisite for effective management of this fishery resource. To date, few studies have investigated intra-Mediterranean swordfish population structure, and their conclusions are controversial. Methods A panel of 20 microsatellites DNA was used to investigate fine-scale population structuring of swordfish from six main fishing areas of the Mediterranean Sea. Results This study provides evidence to reject the hypothesis of a single swordfish population within the Mediterranean Sea. DAPC analysis revealed the presence of three genetic clusters and a high level of admixture within the Mediterranean Sea. Genetic structure was supported by significant FST values while mixing was endorsed by the heterozygosity deficit observed in sampling localities indicative of a possible Wahlund effect, by sampling admixture individuals. Overall, our tests reject the hypothesis of a single swordfish population within the Mediterranean Sea. Homing towards the Mediterranean breeding areas may have generated a weak degree of genetic differentiation between populations even at the intra-basin scale.

Inter- and intraspecific variation of chloroplast mini- and microsatellites DNA in the four closed related Acacia species

Mini- and microsatellites of four Acacia species, A. aulacocarpa, A. auriculiformis, A. crassicarpa and A.mangium were investigated on four non-coding regions of cpDNA, the intron of trnL, and the intergenicspacers of trnL - trnP, trnD - trnY, and trnP – trnW. Nine single base substitutions and six informative miniandmicrosatellites were detected in the the four cpDNA non-coding regions. Based on the substitutionsand mini- and microsatellites, ten cpDNA haplotypes (A - J) could be distinguished. Acacia auriculiformispossessed fi ve haplotypes, A. aulacocarpa, four haplotypes, and A. crassicarpa, three haplotypes. All samplesof A. mangium possessed the same haplotype. Mini- and microsatellites recognized in this study can beused for species identifi cation of the four Acacia species. The ten haplotypes could divided the four speciesinto 2 groups, A. aulacocarpa-A.crassicarpa group and A. auriculiformis-A. mangium group. By developing thePCR-based markers based on the sequence information, many experiments can be carried out for the Acaciaimprovement programs.

Genetic Diversity and Population Structure of a Threatened African Tree Species,Milicia excelsa,Using Nuclear Microsatellites DNA Markers

To accurately estimate the genetic diversity and population structure for improved conservation planning ofMilicia excelsatree, 212 individuals from twelve population samples covering the species' range in Benin were surveyed at seven specific microsatellite DNA loci. All loci were variable, with the mean number of alleles per locus ranging from 5.86 to 7.69. Considerable genetic variability was detected for all populations at the seven loci (AR=4.60;HE=0.811). Moderate but statistically significant genetic differentiation was found among populations considering bothFST(0.112) andRST(0.342). All of the populations showed heterozygosity deficits in test of Hardy-Weinberg Equilibrium and significantly positiveFISvalues due to inbreeding occurring in the species. PairwiseFSTvalues were positively and significantly correlated with geographical distances (r=0.432;P=.007, Mantel's test) indicating that populations are differentiated by “isolation by distance.” Bayesian analysis of population structure showed division of the genetic variation into four clusters revealing the existence of heterogeneity in population genetic structure. Altogether, these results indicate that genetic variation inMilicia excelsais geographically structured. Information gained from this study also emphasized the need for in situ conservation of the relict populations and establishment of gene flow corridors through agroforestry systems for interconnecting these remnant populations.

Sequence-tagged microsatellite site markers for chickpea (Cicer arietinum L.)

Two small-insert genomic libraries of chickpea (Cicer arietinum L.) were screened with a set of microsatellite-specific oligonucleotide probes. A total of 121 positive clones were identified among 13 000 plated colonies. Thirty-nine clones were recognized by (TAA)5, 26 by (GA)8, 18 by (GT)8, 27 by a pool of AT-rich trinucleotide repeats [(CAA)5, (CAT)5, and (GAA)5], and 11 by a pool of GC-rich trinucleotides [(TCC)5, (CAC)5, (CAG)5, and (CGA)5]. Of 53 clones selected for sequencing, 43 carried a microsatellite. Flanking primer pairs were designed for 28 loci, and used on a small test-set comprising one C. reticulatum and four C. arietinum accessions. Separation of the PCR products on agarose or polyacrylamide gels revealed single bands of the expected size with 22 of the primer pairs. Sixteen of these "Cicer arietinum sequence-tagged microsatellite site" (CaSTMS) markers were polymorphic at an intraspecific level, detecting 2-4 alleles within the four accessions examined. Primer pairs CaSTMS10 and CaSTMS15 revealed 25 and 16 alleles among 63 C. arietinum accessions from different geographic locations, reflecting gene diversity values of 0.937 and 0.922, respectively. Mendelian inheritance of CaSTMS markers was demonstrated using a set of recombinant inbred lines and their parents.Key words: chickpea, molecular markers, STMS, microsatellites, DNA polymorphism.