The major histocompatibility complex (MHC) plays a crucial role in the processing and presentation of antigens and in discrimination between self and non-self. The aim of this investigation was to scrutinize the structural diversity and possible duplication of the MHC-DQA genes in yak (Bos grunniens). Two cDNA sequences were amplified and designated as Bogr-DQA1 (DQA*0101) and Bogr-DQA2 (DQA*2001) with GenBank accession numbers JQ864314 and JQ864315, respectively. The nucleotide and amino acid sequence alignment between Bogr-DQA1 and Bogr-DQA2 molecules showed that these two identified MHC-DQA gene sequences had more similarity to alleles of specific DQA1 and DQA2 genes from other Ruminantia species than to each other. The result from phylogenic investigation also revealed that there was a larger genetic distance between these two genes than between homologous genes from different species. The presence of different bovine DQA putative motifs and the large genetic distance between Bogr-DQA1 and Bogr-DQA2 suggest that these sequences are non-allelic. Further, these results indicate that DQA gene duplication occurs in ruminants. This study will be helpful in knowing MHC diversity in common ruminants and will deepen our understanding of the variation of immunological functions, evolutionary constraints, and selective forces that affect MHC variation within and between species.
Tag: molecular genetics
Morphological characterization of Soursop (Annona muricata L.) germplasm in Sri Lanka
Annona muricata L. is an underutilized fruit tree species in Sri Lanka, which is mostly confined to homegardens. Despite the importance of A. muricata, collection, characterization and improvement of its germplasm is limited in Sri Lanka, hence hindered its effective conservation and utilization. Therefore, the objective of this research was to identify morphological variation of A. muricata populations in Sri Lanka. Multistage Sampling Survey was conducted in homegardens of Anuradhapura, Polonnaruwa and Hambantota dictricts in the Dry zone, Puttalama and Kurunagala districts in the AIntermediate zone, and Kalutara and Gampaha districts in the Wet zone. Random representative samples were also collected from existing germplasm collections at three national research centers. Morphological variation of A. muricata were observed on total of 315 samples collected from seven districts of three climatic zones and 133 samples collected from germplasm collections at three national research centers. Forty five morphological characters were recorded from 448 accesions and subjected to Principal Component Analysis (PCA) and Factor Analysis (FA), followed by Cluster Analysis. A dendrogram of evaluated characters showed nine distinguished clusters. Implications of findings are discussed in relation to utilization and conservation.
Potential impact of climate change on termite distribution in Africa
Termites (Order: Isoptera) constitute an integral component of various ecosystems in Africa. Termites are also amongst the most difficult insects to study because of their cryptic behaviour and natural nesting habitat. There are around 2600 species of termites in 280 genera which have been described worldwide and about 39% of the total termite species are found in Africa. Termite identification is crucial to understanding termite distribution and their relationship to climate change. Some termite species are well known pests of agricultural crops, forest trees, wood products and timber-in-service causing considerable damage in Africa. This review paper attempts to collate information on African termite distribution and climate change and highlights some knowledge gaps. Africa is the origin of the termite family of Macrotermitinae. The paper focuses more on economically important termite species in Africa. The use of traditional identification methods coupled with molecular techniques in resolving some of the challenges in termite distribution with particular reference to climate change in Africa are discussed. There is scant information on published literature on the impact of climate change on termites with particular reference to termite distribution in Africa. However there is anectodal evidence to suggest that African termite species will be affected by changes in the local and global climate.