DNA Fingerprinting and Genotyping of Four Black Seed (Nigella sativa L.) Taxa

DNA fingerprints of four Taxa of black seeds (Nigella sativa L.) from Qassim (Saudi Arabia), Ethiopia, Egypt, and Syria were studied. The results showed that there are several genetic differences between these different black seeds Taxa, which could be considered as genotypic characteristics and lead to classifying them as varieties under the sativa species. To study the DNA fingerprinting of these Taxa, the Inter Simple Sequence Repeat (ISSR) method was employed in the PCR technique to determine the levels of polymorphism between their genetic makeups. The ISSR-PCR investigated the intermicrosatellites sequences in their three types (Di, Tri, and Tetra) of the Short Tandem Repeats. Seventeen proper primers representing these three primers types were used. The obtained banding pattern indicated a high level of polymorphism. The scored bands of the DNA fingerprints in these Taxa were 108, 106, 100 and 81 in Qassim, Ethiopia, Syria, and Egypt, respectively. When the percentages of dissimilarity between them were computed, the range was between 21.5-36.3%. Such a relatively high level of polymorphism substantiated the objectives of the present study which supposed that black seeds grown in the different localities in the world over time have undergone genetic changes to the level that could make them different varieties. Twenty four genes representing 24 different enzymes and isozymes were selected and scanned via PCR technique using suitable SSR primers. The obtained results, showed some changes in the genetic structure of some of these genes. The differences in the DNA fingerprints and the number of comparable genes should be reflected on the gene expression manifested in the protein homology and hence on the metabolism.