Fatty acid composition of muscle and heart tissue of Nile perch,Lates niloticus,and Nile tilapia,Oreochromis niloticus,from various populations in Lakes Victoria and Kioga,Uganda

The fatty acid composition in the heart tissue and muscle tissue of the Nile perch, Lates niloticus, and Nile tilapia, Oreochromis niloticus populations from Lakes Kioga and Victoria was determined by methanolysis and gas chromatography of the resulting fatty acid methyl esters. The analytical data were treated by multivariate principal component analysis. The most abundant individual fatty acids were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1n9), vaccenic acid (18:1n7), arachidonic acid (20:4n6) and docosahexaenoic acid (22:6n3). Due to high levels of both n6 and n3 fatty acids, the ratios of n3 to n6 were between 1 and 2, typical for freshwater fish species. Two Lake Victoria and one Lake Kioga populations of Nile tilapia and Nile perch were distinguished by the fatty acid profiles in their heart and muscle tissue. The heart tissue showed better separation than muscle tissue, due to dominance of polar phospholipids. It is rationalised that genetics are more important than diet in determining the fatty acid composition of the tissues.     

Notes on African Mosses. I. Andreaea camerunensis sp.nov. and other Mosses mostly from Nigeria and the British Cameroons

Abstract

Reproductive ecological traits such as success of fertilization, partitioning of sexes, the relative success of sexual versus asexual reproduction and dispersal distances are likely to considerably influence genetic structure within and among plant populations. In the liverwort Mannia fragrans both sexual and asexual reproduction can be frequently observed: sporophytes are produced abundantly every year and asexual propagation by fragmentation of thalli is also common. The aim of this study was to use ecological and molecular methods (ISSR markers) to separate the role of sexual and asexual components in shaping the partitioning of genetic variability within and among populations. In addition to genetic analyses conducted seasonally, sex expression and fertilization rates, sex ratios, regeneration from vegetative fragments and outcrossing was estimated in 3 populations of the species. Sex expression rates were high and, in spite of strongly female biased sex ratios, high fertilization rates were detected. However, capacity for regeneration from fragments was also high. Despite frequent spore production genetic diversity was low within populations. This is probably the result of the predominance of asexual reproduction s. 1. including crossing between genetically identical plants. Although recombination and mutation occasionally generates new haplotypes, these have little chance to spread because of the large spores mainly falling into their own patch, where chances for germination are low. Due to small size and isolation of the populations, genetic drift is likely to eliminate these haplotypes. Remote populations differed significantly, each being dominated by a few clones, reflecting negligible gene flow among them. Differences among individual populations can partly be related to differences in their reproductive behaviour and degree of isolation.     

Extensive Genetic Polymorphism of Peptidases A, B, C, and D, in Wild Rabbit (Oryctolagus cuniculus) Populations from the Iberian Peninsula

Genetic polymorphism of peptidases A, B, C, andD in the wild rabbit (Oryctolagus cuniculus)was assessed by horizontal starch gel electrophoresis,in a total of 1003 individuals comprising 16 Iberian and 2 French populations and 1 domestic stock.Twenty-five different alleles were detected: 6 in PEPA,4 in PEPB, 8 in PEPC, and 7 in PEPD. The highest valuesof observed heterozygosity averaged over the four loci were obtained for the southwestern Iberianpopulations and a clinal loss of variability in anortheastern direction was detected. A clear separationbetween the two putative subspecies O. c.cuniculus and O. c. algirus was notobtained.     

Aerial and underground biomasses of three Sphagnum-dwelling liverworts

Abstract

The few studies that have investigated levels of genetic variation in liverworts have found very little polymorphism. Our electrophoretic data show, however, that the leafy liverwort Porella platyphylla maintains high levels of genetic variation in at least some natural populations from the southeastern United States. Within a single population from southwestern North Carolina, we detected 26 distinct multilocus genotypes and more than 80% of the enzyme loci we surveyed were polymorphic. It seems likely that earlier studies of mostly thalloid species from glaciated regions of Europe have presented a biased picture of levels of variation in liverwort populations.     

Genetic Diversity of Chinese Native Pigs Inferred from Protein Electrophoresis

We examined protein polymorphism of 20 nativepig breeds in China and 3 introduced pig breeds. Thirtyloci have been investigated, among which six loci werefound to be polymorphic. Especially, the polymorphismof malate dehydrogenase (MDH), adenylate kinase(AK), and two new alleles of adenosine deaminase (ADA)had not been reported in domestic pigs and wild pigs.The percentage of polymorphic loci (P), the meanheterozygosity (H), and the mean number ofalleles (A) are 0.200, 0.065, and 1.300, respectively.The degree of genetic variability of Chinese pigs as awhole was higher than that of goats, lower than thatof cattle and horses, and similar to that ofsheep. Using the gene frequencies of the 30 loci, Nei'sgenetic distance among the 20 native breeds in China and3 introduced pig breeds was calculated by theformula of Nei. The program NEIGHBOR in PHYLIP3.5c was chosen to construct an UPGMA tree and a NJtree. Our results show that, of the total geneticvariation found in the native pig breeds in China, 31%(0.31) is ascribable to genetic differencesamong breeds. About 69% of the total genetic variationis found within breeds. Most breeds are in linkagedisequilibrium. The patterns of genetic similaritiesbetween the Chinese native pig breeds were notin agreement with the proposed pig type classification.     

Electrophoretic Polymorphisms and Their Taxonomic Implications in Callitrichini (Primates, Platyrrhini)

Five hundred forty-three blood samples from 15populations of the four genera of callitrichin primateswere studied electrophoretically. Polymorphism andgenetic distances were estimated for 20 loci, 13 of which were polymorphic. The lion tamarin(Leontopithecus) studied here exhibited theleast variability for these loci, while the monospecificCebuella showed the most. The genetic distancesobserved between Callithrix andCebuella genera support previous evidenceindicating a close taxonomic relationship between them.Genetic distance values obtained in this study alsosupport the synonimization of the kuhli form with Callithrix jacchuspenicillata.     

Genetic Diversity of Yunnan Local Pig Breeds Inferred from Blood Protein Electrophoresis

Protein electrophoresis was used to examine theblood protein polymorphism in Yunnan local pig breeds,i.e., the Saba pig, Dahe pig, and Diannan small-ear pigbreeds. Of 38 genetic loci surveyed, 9 were found to be polymorphic. The percentage ofpolymorphic loci (P) varies from 0.1875 to 0.2121, andthe mean individual heterozygosity (H) varies from0.0712 to 0.1027 in three pig breeds. The resultsindicate that blood protein polymorphism in Yunnan pigbreeds is high. Yunnan local pig breeds have a wealth ofgenetic diversity at the level of blood proteins.     

Genetic Variation and Phylogenetic Relationships Among Six Populations of Corn Borers in China

The genetic variation among and within sixpopulations of the corn borer was determined by usingrandom amplified polymorphic DNA (RAPD) markers.Extensive genetic variability was detected. Of the 802RAPD markers obtained, 781 (97.4%) were polymorphicamong populations. Genetic similarities and distancesbetween each pair of individuals were calculated. UPGMAcluster analysis showed that the YN population (Ostrinia nubilalis Hubner) and the other fivepopulations (Ostrinia furnacalis Guenee) made upbranches of the corn borer lineage, instead ofdeviating; there was no significant geneticdifferentiation between YN and the other five corn borerpopulations.