in an attempt to characterize theileria parva parasites circulating in south sudan cattle , polymerase chain reaction (pcr)-based assays were carried out using four single copy encoding antigen genes p104, pim, p150 and p67 in addition to one microsatellite ms321. a total of 20 bovine dna samples from two locations in south sudan were included in this study, in addition to two references strain...

Self-incompatibility (SI) systems are widespread mechanisms that prevent self-fertilization in angiosperms. They are generally encoded by one genome region containing several multiallelic genes, usually called the S-locus. They involve a recognition step between the pollen and the pistil component and pollen is rejected when it shares alleles with the pistil. The direct consequence is that rare...

The recent identification of the long elusive pollen determinant of self-incompatibility (SI) in the Brassicaceae family (Schopfer et al., 1999) marks a major advance in SI research. Not only is it now unambiguously proven that in the genus Brassica SI specificity of pollen and stigma is governed by separate genes, but in addition, the availability of the pollen specificity gene opens new avenu...

The recent identification of the long elusive pollen determinant of self-incompatibility (SI) in the Brassicaceae family (Schopfer et al., 1999) marks a major advance in SI research. Not only is it now unambiguously proven that in the genus Brassica SI specificity of pollen and stigma is governed by separate genes, but in addition, the availability of the pollen specificity gene opens new avenu...

Many flowering plants are unable to set seeds with their own pollen because a system known as gametophytic self-incompatibility is operating. The basis of this system is a single multiallelic locus S, and if the S allele carried by a pollen grain matches one of the two S alleles carried in the style, as it is certain to do upon self-pollination, then pollen tube growth is inhibited. Should one ...

background: the human leukocyte antigen-drb1 (hla-drb1) locus is one of the most polymorphic human loci and has a crucial role in the immune system. assessing the allelic frequencies of hla-drb1 locus would be a fundamental factor in defining the origin of populations, relationships with other populations, disease association studies and the constitution of unrelated bone marrow donor registrie...

The self-incompatibility (S) genes of flowering plants are, with the fungal incompatibility and mammalian major histocompatibility (MHC) loci, among the most highly polymorphic loci known. In Oenothera organensis, for example, 35 alleles have been detected [1] by laborious compatibility tests between plants of this endemic species, the total population size of which may not exceed 5000 [2]. Dif...

Self-incompatibility (SI) is a genetic system found in some hermaphrodite plants. Recognition of pollen by pistils expressing cognate specificities at two linked genes leads to rejection of self pollen and pollen from close relatives, i.e., to avoidance of self-fertilization and inbred matings, and thus increased outcrossing. These genes generally have many alleles, yet the conditions allowing ...