ASSESSMENT OF GENETIC VARIATION AMONG PISTACIA ATLANTICA DESF. REGARDING SEXUAL GENOTYPES (MALE, FEMALE AND HERMAPHRODITIC) USING ISSRS. MARKERS

All Pistacia species are dioecious, male and female flowers are born on separated trees. Our recent studies identified new hermaphroditic genotypes of P. atlantica with different structure of racemes and flowers at the south of Syria. Therefore, the current research aimed to assess genetic variation among 11 genotypes (3 female, 5 hermaphroditic, 3 male) across fifteen ISSRs primers in Sweida Research Center (2018-2019). All of the primers were able to detect the polymorphism, which revealed 214 bands, 205 of them were polymorphic (95.79%). The number of bands for each primer ranged from 6 to 33, with an average 14.27 bands for each Primer. Genetic similarity among all studied genotypes ranged from (0.27) between hermaphroditic genotype (PA52) with female genotype (FA3) as well as between MA3 male genotype and FA2 female genotype, while the highest genetic similarity was 0.77 between two hermaphroditic genotypes (PA37and PA52). Cluster analysis grouped all studied genotypes into three main clusters according to their sexual structure; the first cluster contained all of the hermaphroditic genotypes and the second cluster comprised of all male genotypes, while the third cluster included all female genotypes. The results demonstrated the importance and the efficiency of ISSR technique by revealing the genetic variation among P. atlantica genotypes and separating all of them into detached clusters according to their sexual structure. Farther more, some primers were able to detect common bands in each sexual structure which might help to understand the mechanism of sexual inheritance within the studied species.

Triparental inheritance inDictyostelium

Sex promotes the recombination and reassortment of genetic material and is prevalent across eukaryotes, although our knowledge of the molecular details of sexual inheritance is scant in several major lineages. In social amoebae, sex involves a promiscuous mixing of cytoplasm before zygotes consume the majority of cells, but for technical reasons, sexual progeny have been difficult to obtain and study. We report here genome-wide characterization of meiotic progeny inDictyostelium discoideum. We find that recombination occurs at high frequency in pairwise crosses between all three mating types, despite the absence of the Spo11 enzyme that is normally required to initiate crossover formation. Fusions of more than two gametes to form transient syncytia lead to frequent triparental inheritance, with haploid meiotic progeny bearing recombined nuclear haplotypes from two parents and the mitochondrial genome from a third. Cells that do not contribute genetically to theDictyosteliumzygote nucleus thereby have a stake in the next haploid generation.D. discoideummitochondrial genomes are polymorphic, and our findings raise the possibility that some of this variation might be a result of sexual selection on genes that can promote the spread of individual organelle genomes during sex. This kind of self-interested mitochondrial behavior may have had important consequences during eukaryogenesis and the initial evolution of sex.