The Nigerian indigenous pigs (NIP) are threatened to lose their genetic diversity through unsustainable farming practices in Nigeria. Therefore, the genetic relationships of NIP and commercially developed cross-bred pigs were evaluated to pinpoint a possible source of pure uncontaminated genetic stocks of NIP for conservation. Blood protein polymorphisms were used as a preliminary genetic analysis of blood samples from a total of 120 pigs (79 NIP from three separate locations and 41 cross-bred pigs). Nineteen polymorphic bands of the blood proteins globulin, transferrin and albumin were observed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and a phylogenetic dendrogram was developed to analyse the genetic relationship between the NIPs. The three NIPs were found to have a high genetic similarity (84 percent similarity coefficient), and were found to be distinctly different from the commercially cross-bred strains. One line from a farm in Ogbooro, Saki Oyo, Nigeria was identified as a relatively stable genetic resource that may be a suitable NIP for future conservation efforts.

Introduction. This protocol applies to the characterization of genome structure and evolution of M. acuminata and M. balbisiana genomes; construction of physical maps around markers of interest and QTLs; comparative genomic studies with other monocot species; and study of banana streak virus (BSV) integration patterns in banana nuclear genomes. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required materials, and the protocols for isolation and lysis of banana nuclei; high-molecular-weight (HMW) DNA Hind III digestion and pulsed-field gel electrophoresis (PFGE) analysis; large-scale HMW DNA Hind III digestion and ligation to the pINDIGOBAC–5 vector; and analysis of recombinant BAC clones. It mentions the main problems which can occur. Results. The described protocols will enable the efficient construction of BAC libraries from Musa species. These libraries can be used to construct physical maps and select specific genomic regions to be sequenced.

Introduction. The Tephritidae Ceratitis capitata is one of the most important agricultural pests in the world. Eradication programmes need as much genetic information as possible to be efficient. It is vital to know the genetic variation that exists in the areas thought to have been important in the expansion of the species, such as the Iberian Peninsula. The aim of this study was to determine the genetic structure of Spanish C. capitata populations and the relationships between them. Materials and methods. We studied the genetic variability of populations of C. capitata (eight wild samples and one laboratory strain) through the use of the horizontal starch gel electrophoresis technique and the assay of fifteen enzyme-coding loci chosen at random. Results. The quantity of variability detected in this polyphagous species was not high. Of the 15 loci studied, only four were clearly polymorphic. No significant differences were found in any comparison of populations collected from different hosts. Discussion. The distribution patterns of this variation seem to be the result of gene flow and selection in the form of agricultural practices.

Starch gel electrophoresis was used to compare eight loci in six enzymatic systems of 17 samples of the groundnut seed-beetle, Caryedon serratus (Ol.) (Coleoptera: Bruchidae) bred on five different host-plant species: Arachis hypogaea, Bauhinia rufescens, Cassia sieberiana, Piliostigma reticulatum and Tamarindus indica. The rate of polymorphism was 44.8%. The average genetic diversity (Hw) was 0.184. Allozyme variability analysis indicated that seed-beetles associated with P. reticulatum and groundnut, Arachis hypogaea were genetically similar, whereas other samples clustered according to their host plant species. Geographical distances less than 400 km were not decisive for the genetic structuring of samples associated with a given host plant.

The banding patterns of six soluble enzymes of a Sogatella furcifera Horvath population from Sri Lanka, maintained in glass-houses on rice variety TN 1 at University of Wales, Cardiff, were studied. Crude homogenates of macropterous adults of both sexes were analysed, using polyacrylamide electrophoresis. The following enzymes showed activity and were stained: esterase (EST), lactate dehydrogenase (LDH), phosphoglucomutase (PGM), hexokinase (HK), glucose-6-phosphate dehydrogenase (G-6-PDH) and malic enzyme (ME). Number and relative mobility of bands varied between enzyme systems.

Introgression between introduced domesticated stocks and natural populations of brown trout was investigated by protein electrophoresis in three Mediterranean rivers. From each river, one undisturbed site and one, closely located, yearly stocked site were sampled. Comparison of the electrophoretic variation observed in samples from the undisturbed sites with that in the introduced hatchery strains revealed several specifically "domestic" variants. The genetic control of these variants was demonstrated by breeding experiments. The samples collected from the stocked sites showed introgression rates ranging from approximately 0 to 40%. The genotype frequencies observed in these samples suggested that no reproductive barrier exists between introduced and native stocks and that they form random mating populations.