Oluwatoyin Temitayo Ogundipe

Partitioning and distribution of random amplified polymorphic DNA (RAPD) variation among eggplant Solanum L. in Southwest Nigeria

Solanum L., the largest genus of the Solanaceae family, vary morphologically, is diverse in number and is ecogeographically distributed. In Nigeria, previous studies had focused mainly on chromosome morphology, genome description and medicinal values, which are insufficient for genetic affinities. This study used four highly polymorphic random amplified polymorphic DNA primers to describe both the genetic relatedness and variability among 25 accessions of eggplant from Southwestern Nigeria. At a truncated line of 65%, five clusters and two ungrouped samples are distinguishable from the dendrogram. The data reveals that Solanum dasyphyllum Schum. & Thonn. is more closely related to Solanum macrocarpon L. than to Solanum melongena L. The relatedness between Solanum incanum L. and Solanum melongena, a probability of being progenitors from a common ancestral lineage was also shown. Occurrence of Solanum scabrum L. and Solanum nigrum L. in the same clusters different from S. melongena, is an indication of distant relatedness to S. melongena but close relatedness between them. High level of polymorphism was observed in this study going by the coefficient of variation which exhibited a good separation from a conserved region of the genome. This study, therefore, reveals a wide and diverse genetic base in Nigerian eggplant Solanum. Key words: Eggplant, genome, synonymy, polymorphism, phylogenetic.

Genetic diversity and distribution of Senegalia senegal (L.) Britton under climate change scenarios in West Africa

Climate change is predicted to impact species’ genetic diversity and distribution. We used Senegalia senegal (L.) Britton, an economically important species distributed in the Sudano-Sahelian savannah belt of West Africa, to investigate the impact of climate change on intraspecific genetic diversity and distribution. We used ten nuclear and two plastid microsatellite markers to assess genetic variation, population structure and differentiation across thirteen sites in West Africa. We projected suitable range, and potential impact of climate change on genetic diversity using a maximum entropy approach, under four different climate change scenarios. We found higher genetic and haplotype diversity at both nuclear and plastid markers than previously reported. Genetic differentiation was strong for chloroplast and moderate for the nuclear genome. Both genomes indicated three spatially structured genetic groups. The distribution of Senegalia senegal is strongly correlated with extractable nitrogen, coarse fragments, soil organic carbon stock, precipitation of warmest and coldest quarter and mean temperature of driest quarter. We predicted 40.96 to 6.34 per cent of the current distribution to favourably support the species’ ecological requirements under future climate scenarios. Our results suggest that climate change is going to affect the population genetic structure of Senegalia senegal, and that patterns of genetic diversity are going to influence the species’ adaptive response to climate change. Our study contributes to the growing evidence predicting the loss of economically relevant plants in West Africa in the next decades due to climate change.

Aeropalynological study of two selected locations in North-Central Nigeria

Abstract Pollen and spores have been found as major biological sources of morbidity among individuals sensitive to respiratory disorders. The aim of the present study was to analyse the deposition rate of atmospheric pollen and fern spores at selected sites in Benue and Plateau states of the North-Central Nigeria between July 2015 and June 2016. This was accomplished by: (1) determining the pollen and fern spore content of each monitoring station; (2) establishing the relationship between total pollen count and meteorological parameters; and (3) comparing the recovered airborne pollen spectra with identified plants in the surrounding vegetation types of the sampling sites. The collection of atmospheric pollen was done using a modified Tauber sampler and plants in the surrounding environment of the sampling sites were enumerated. The residual solution was collected monthly and acetolysed, after which slide preparation and microscopy of the treated residue were done. Meteorological data were obtained from the Nigerian Meteorological Agency, Lagos. The results obtained reveal seasonal distribution patterns of various airborne pollen grains in the study locations. The most abundant pollen types recovered in Plateau State were produced by Syzygium guineense, Tridax procumbens, Alchornea sp., Terminalia sp., Poaceae and Amaranthaceae. Pollen types of Casuarina equisetifolia, Syzygium guineense, Tridax procumbens, Poaceae and Cyperaceae were preponderant in Benue State. Pteris sp., Nephrolepis sp. and a trilete fern spore were also represented in this study. The recovered airborne pollen spectra correspond favourably with some identified plants in the study locations. There was no significant correlation between monthly total pollen count and mean monthly values of meteorological parameters in Benue State. Air temperature and wind speed correlated significantly with monthly total pollen count in Plateau State. It is suggested that the allergenic effect of these abundant pollen types on humans should be further examined.

Genetic diversity in Nigerian brinjal eggplant (Solanum melongena L.) as revealed by random amplified polymorphic DNA (RAPD) markers

The taxonomy of Solanum melongena L., also known as brinjal eggplant, has remained difficult because previous studies to establish genetic relationships among taxa are mainly based on morphological features, which are insufficient to establish genetic affinities. In the present investigation, five highly polymorphic random amplified polymorphic DNA primers were used to describe the genetic similarity and diversity among its accessions in Nigeria. The results show a high level of polymorphism based on the banding patterns among the samples. This indicated a wide and diverse genetic base. Four distinct clusters were equally noticeable at a coefficient of 0.80 from the dendrogram generated. Generally, the grouping pattern clearly indicates that irrespective of variations in fruit traits among samples, they were still grouped together in different clusters with a high similarity coefficient value. This probably showed some genetic relatedness/closeness among the samples concerned. The study also revealed that there is no association between RAPD pattern and the geographic origin of accessions. These agreed with previously published data on the characterization of eggplant. The study disclosed that molecular methods coupled with morphological analyses could make proper classification of S. melongena and other Solanum species in Nigeria possible to achieve. Keywords: Eggplant, random amplified polymorphic DNA (RAPD), Data, polymorphism, taxonomy African Journal of Biotechnology , Vol 13(21) 2119-2126

Pleistocene refugia and genetic diversity patterns in West Africa: Insights from the liana Chasmanthera dependens (Menispermaceae)

Processes shaping the African Guineo-Congolian rain forest, especially in the West African part, are not well understood. Recent molecular studies, based mainly on forest tree species, confirmed the previously proposed division of the western African Guineo-Congolian rain forest into Upper Guinea (UG) and Lower Guinea (LG) separated by the Dahomey Gap (DG). Here we studied nine populations in the area of the DG and the borders of LG and UG of the widespread liana species, Chasmanthera dependens (Menispermaceae) by amplified fragment length polymorphism (AFLP), a chloroplast DNA sequence marker, and modelled the distribution based on current as well as paleoclimatic data (Holocene Climate Optimum, ca. 6 kyr BP and Last Glacial Maximum, ca. 22 kyr BP). Current population genetic structure and geographical pattern of cpDNA was related to present as well as historical modelled distributions. Results from this study show that past historical factors played an important role in shaping the distribution of C. dependens across West Africa. The Cameroon Volcanic Line seems to represent a barrier for gene flow in the present as well as in the past. Distribution modelling proposed refugia in the Dahomey Gap, supported also by higher genetic diversity. This is in contrast with the phylogeographic patterns observed in several rainforest tree species and could be explained by either diverging or more relaxed ecological requirements of this liana species.