Agreement with locatives in Kinyarwanda: a comparative analysis

In Bantu languages such as Chichewa or Herero, locatives can function as subjects and show noun class agreement (in class 16, 17 or 18) with predicates and modifiers. In contrast, (preverbal) locatives in Sotho-Tswana and Nguni have been analysed as prepositional adjuncts, which cannot agree. Our paper compares locatives in Kinyarwanda (JD61) with locatives in these other Bantu languages and demonstrates that the Kinyarwanda locative system is essentially of the Chichewa/Herero type. We show that Kinyarwanda locatives are nominal in nature, can act as subjects, and agree with predicates and modifiers. However, even though Kinyarwanda has four locative noun classes (16, 17, 18 and 25), there is only one locative agreement marker (class 16ha-), which indiscriminately appears with all locatives, regardless of their noun class. We explain this fact by arguing that noun class features in Kinyarwanda do not participate in locative agreement; instead, the invariant class 16 marker expresses agreement with a generic feature [location] associated with all locatives. We offer a syntactic analysis of this peculiar aspect of Kinyarwanda locative agreement, and we propose a parameter that accounts for the relevant difference between Kinyarwanda and Chichewa/Herero-type Bantu languages.

Comparative analysis of genetic relationships in barley based on RFLP and RAPD markers

Genetic relationships have seldom been analyzed with different types of molecular markers in order to compare the information provided by each marker class. We investigated genetic relationships among nine barley cultivars using separate cluster analyses based on restriction fragment length polymorphisms (RFLPs) and random amplified polymorphic DNAs (RAPDs). Genomic DNA restricted with three enzymes and hybridized with 68 probes revealed 415 RFLPs (74.2% of all bands). Among the 128 primers used for RAPD analysis, 100 provided a reproducible profile, 89 of which revealed 202 polymorphic and 561 monomorphic bands (26.5 and 73.5%, respectively). A nonrandom distribution of 62 RAPDs with a tendency to cluster near centromeric regions was produced when these RAPDs were mapped using 76 doubled-haploid lines derived from a cross between two of the nine cultivars. The correlation between the RFLP and RAPD similarity matrices computed for the 36 pairwise comparisons among the nine cultivars was equal to 0.83. The dendrograms obtained by cluster analyses of the RFLP and RAPD data differed. These results indicate that in barley the information provided by RFLPs and RAPDs is not equivalent, most likely as a consequence of the fact that the two marker classes explore, at least in part, different portions of the genome.Key words: Hordeum vulgare L., genetic distance, molecular markers, cluster analysis.

The calculation of recombination frequencies in crosses of allogamous plant species with applications to linkage mapping

SummaryThe recombination frequency (r) between two loci defined by conventional or molecular markers can be estimated by solving proper Maximum Likelihood equations. These are based on expected and observed marker class frequencies in the progeny of a cross, and are specific for each allelic configuration of the parents(1). In a cross between two diploid parents up to four different alleles, besides a null allele, can be detected at one locus. This defines in each parent, considering a locus A, nine basic allelic configurations based on two allelic marker fragments(Ai/Aj), one single marker allele and a null allele (Ai/AO), or just null alleles (AO/AO). With respect to two loci the consideration of all possible diploid allelic configurations in the parents of a cross allows the detection of 21 different expected marker class distributions producing estimates of r in the progeny. General formulas for calculating the ML equations and the corresponding information functions have been developed for the 21 marker class distributions. Simplified formulas have been also derived and the relative efficiency of the information functions compared. As expected, in the majority of cases, allelic marker configurations give more precise estimates of linkage values than single marker configurations. A method for the construction of linkage maps based on two point estimates, linkage subgroups and allelic bridges is presented. The method is an improvementon an original proposal by Ritter et al.(1990).