Blood genetic marker studies of a sheep-goat hybrid and its back-cross offspring

Summary. Blood samples from a female sheep-goat hybrid and its back-cross male offspring were tested for electrophoretic variants of plasma albumin, transferrin and esterase, and of red cell carbonic anhydrase, nucleoside phosphorylase, NADH-diaphorase, 'X'-protein, superoxide dismutase, malic enzyme and haemoglobin. Red cells were also tested for blood group antigens. Both animals showed variants that could not be attributed to either sheep or goat alone, thus confirming previous chromosomal data that the female was a genuine sheep-goat hybrid.     

Hydrogenosome-Methanogen Assemblages in the Echinoid Endocommensal Plagiopylid Ciliates,Lechriopyla mystax Lynch, 1930 and Plagiopyla minuta Powers, 19331

ABSTRACT. Lechriopyla mystax Lynch, 1930 and Plagiopyla minula Powers, 1933 contain hydrogenosome-methanogen assemblages similar to those reported for other plagiopylid ciliates. These assemblages are stacks of elongate ovoid hydrogenosomes alternating with methanogens; these stacks are surrounded by cisternae of the rough endoplasmic reticulum that are often accompanied by Golgi complexes. The individual methanogens in the larger ciliate, L. mystax, are about four times the volume of those in the smaller ciliate, P. minuta, but both ciliates appear to contain Gram-negative methanococcoid bacteria, possibly Methanoplanus sp. The endoplasmic reticulum-Golgi complex probably plays a significant role in exploitation of the methanogens by the host ciliate.     

Rapid Homogenization of Multiple Sources: Genetic Structure of a Recolonizing Population of Fishers

Abstract: Fishers (Martes pennanti) were extirpated from much of southern Ontario, Canada, prior to the 1950s. We hypothesised that the recent recolonization of this area originated from an expansion of the population in Algonquin Provincial Park, which historically served as a refuge for fishers. To test this hypothesis, we created a sampling lattice to encompass Algonquin and the surrounding area, and we collected contemporaneous DNA samples. We sampled fishers from each of 35 sites and genotyped them at 16 microsatellite loci. Using a Bayesian assignment approach, with no a priori geographic information, we inferred 5 discrete genetic populations and used genetic population assignment as a means to cluster sites together. We concluded that the Algonquin Park fisher population has not been a substantial source for recolonization and expansion, which has instead occurred from a number of remnant populations within Ontario, Quebec, and most recently from the Adirondacks in New York, USA. The genetic structure among sampling sites across the entire area revealed a pattern of isolation-by-distance (IBD). However, an examination of the distribution of genetic structure (F_ST/1^- F_ST) at different distances showed higher rates of gene flow than predicted under a strict IBD model at small distances (40 km) within clusters and at larger distances up to 100 km among clusters. This pattern of genetic structure suggests increased migration and gene flow among expanding reproductive fronts.     

Stockwellia quadrifida (Myrtaceae), a new Australian genus and species in the eucalypt group

A new genus and species in the eucalypt group of the Myrtaceae is described. Stockwellia quadrifida D.J. Carr, S.G.M. Carr & B.Hyland gen. et sp. nov. is a rainforest tree of restricted distribution on the Atherton Tableland, North Queensland, Australia. Molecular data suggest that it is the sister taxon to Eucalyptopsis and this is supported by morphological characters. The prolonged hypanthium and reduced perianth appear to be synapomorphies for these two genera and the circumscissile hypanthium a synapomorphy shared with Allosyncarpia . Stockwellia differs from Eucalyptopsis by the distinct, albeit reduced, perianth and the hypanthium splitting into four segments at anthesis. The relationship of these two genera indicates an historical biogeographical link between New Guinea and the Queensland wet tropics region.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 415–421.     

Inhibition of development of Meloidogyne incognita by root and foliar applications of oxamyl

Oxamyl (2.5 μg cm^-3sand) applied to the roots of cucumber seedlings significantly reduced the number of vermiform second stage juveniles of Meloidogyne incognita which developed into swollen forms for at least 30 days. However, when cucumber seedlings containing nematodes were removed from oxamyl-treated sand 10 days after the pesticide was applied and placed in clean sand a large proportion of the juveniles had become swollen after a further 18 days. This suggested the effect of oxamyl on nematode development was reversible. A single foliar application of oxamyl (25–100 μg) in distilled water was also found to significantly reduce development of second stage juveniles to saccate forms However, the use of various adjuvants with a threshold foliar treatment (25 μg oxamyl) failed to significantly improve its activity.     

Geometric morphometric analysis of a new Miocene bumble bee from the Randeck Maar of southwestern Germany (Hymenoptera: Apidae)

The first fossil bumble bee (Apinae: Bombini) from the Miocene Randeck Maar of southwestern Germany is described and illustrated. The specimen is subjected to a geometric morphometric analysis along with a diversity of other bumble bee species representing most major extant lineages, and particularly the subgenus Bombus s.s. The morphometric analysis supports the placement of the Randeck Maar species within Bombus s.s., as a species distinct from all others in the subgenus. It shows that extant subgenera of bumblebees were already derived in the early/middle Miocene. The Randeck Maar fossil is formally described as Bombus (Bombus) randeckensis Wappler & Engel sp. n. .     

Demographic genetics of the American beech, Fagus grandifolia. II. Genet substructure of populations for the Blue Ridge, Piedmont and the Great Smoky Mountains

Populations of American beech in Virginia and the Great Smoky Mountain National Park in Tennessee and North Carolina were investigated for demographic genetic substructurings. Two Virginia populations, one on the Blue Ridge (WG1) and the other on the Piedmont (WG2) occur over an elevational gradient of several hundreds meters. One of the Great Smoky Mountain populations (GS1) was in a 'beech gap' and the other (GS2) in a 'cove forest' along a creek. The populations in the Great Smoky Mountain National Park were only separated by a few hundred meters in elevation, but both on the same physiographic province. The populations had two growth forms. Trees produced extensive root suckers at WG1, GS1 and GS2, but WG2 had no root suckers and all individuals had obviously been established from seeds. A total of 1335 shoots were mapped at the four sites, their size measured [diameter at breast height (DBH) or diameter at ground height (DGH)], and genotypes were determined for each locus using allozyme analysis. F_IS among five different size-classes revealed an excess of homozygotes in WG1, GS1 and GS2, and an excess of heterozygotes in WG2. The offshoot formation from root suckers obviously contributed to the abundance of intermediate size-classes in WG1, GS1 and GS2. Exceedingly localized patchiness of different multilocus genotypes reveals genetic clustering of shoots that have obviously originated from root suckers in WG1, GS1 and GS2. The Piedmont population (WG2), on the other hand, showed loose localization of genetically related trees at a scale of 35–40 m in area, suggesting broader ranges of pollen and seed dispersal. The data are discussed in the light of the differences in growth form and mode of reproduction, and also in relation to the post-glacial migration and the current geographic distribution of the species.