Allozyme and Other Aspects of Variation in the Genus Bulbinella in New Zealand

<p>This thesis examines some aspects of morphological, cytogenetic and allozyme variation in the six species of the genus Bulbinella in New Zealand. Because evidence was found suggesting that fragmentation and reduction of the habitat of some species of the study genus had occurred, aspects of the conservation status of Bulbinella were also investigated. Some of the morphological characters described and used by Moore (1964) to separate the species were employed in this study as well as other characters recorded by the author in actively glowing plants. Generally, the seven taxa could be successfully distinguished using selected morphological characters, although in some species or populations a range of morphological forms was observed. Increased human land use (mainly mining, farming and associated activities) has reduced some populations of Bulbinella to low numbers by destroying large areas of habitat. In some cases once vast areas of Bulbinella have been reduced to fragments or probably exterminated. The karyotypes of five of the seven taxa were determined and these were all consistent with published data. G-banding was achieved in only one slide from one plant. A total of four bands (restricted to two pairs of chromosomes) was observed in the entire chromosome complement of 14. Each band was located on a separate chromosome. Inflorescence material from 61 natural populations of Bulbinella in New Zealand was examined for enzyme activity using starch gel electrophoresis. Activity was detected for eight of a total of 43 enzyme stains. Three monomorphic and 11 polymorphic loci were resolved. While no completely fixed differences between all the taxa could be demonstrated, four almost fixed differences were found. In some instances where populations belonging to different species were not geographically separated by great distances (<50km) shared alleles between species were demonstrated, indicating that introgression had occurred and may still be taking place. Overall, the genetic distance (Nei 1978) within taxa was less than that between taxa. The dendrogram resulting from cluster analysis of Nei's unbiased genetic distances divided the genus into four groups, three of which corresponded to three currently recognised taxa. The other group contained the remaining four taxa. Although the component taxa of this cluster could be readily separated using morphological characters, they could not be distinguished using allozyme data. The endemic distribution of B. rossii (Campbell Island and Auckland Island Group) and fixed morphological differences justify its remaining a separate taxon. The formal raising of B. gibbsii var. gibbsii to a separate specific status is subject to the analysis of further samples of this taxon. B. angustifolia, B, talbotii, and B. gibbsii vat. balanifera also remain separate taxa, with B. gibbsii var. balanifera being raised to a separate specific status. B. modesta, which is genetically closely related to B. hookeri, becomes a sub-species of this taxon.</p>

Allozyme and Other Aspects of Variation in the Genus Bulbinella in New Zealand

<p>This thesis examines some aspects of morphological, cytogenetic and allozyme variation in the six species of the genus Bulbinella in New Zealand. Because evidence was found suggesting that fragmentation and reduction of the habitat of some species of the study genus had occurred, aspects of the conservation status of Bulbinella were also investigated. Some of the morphological characters described and used by Moore (1964) to separate the species were employed in this study as well as other characters recorded by the author in actively glowing plants. Generally, the seven taxa could be successfully distinguished using selected morphological characters, although in some species or populations a range of morphological forms was observed. Increased human land use (mainly mining, farming and associated activities) has reduced some populations of Bulbinella to low numbers by destroying large areas of habitat. In some cases once vast areas of Bulbinella have been reduced to fragments or probably exterminated. The karyotypes of five of the seven taxa were determined and these were all consistent with published data. G-banding was achieved in only one slide from one plant. A total of four bands (restricted to two pairs of chromosomes) was observed in the entire chromosome complement of 14. Each band was located on a separate chromosome. Inflorescence material from 61 natural populations of Bulbinella in New Zealand was examined for enzyme activity using starch gel electrophoresis. Activity was detected for eight of a total of 43 enzyme stains. Three monomorphic and 11 polymorphic loci were resolved. While no completely fixed differences between all the taxa could be demonstrated, four almost fixed differences were found. In some instances where populations belonging to different species were not geographically separated by great distances (<50km) shared alleles between species were demonstrated, indicating that introgression had occurred and may still be taking place. Overall, the genetic distance (Nei 1978) within taxa was less than that between taxa. The dendrogram resulting from cluster analysis of Nei's unbiased genetic distances divided the genus into four groups, three of which corresponded to three currently recognised taxa. The other group contained the remaining four taxa. Although the component taxa of this cluster could be readily separated using morphological characters, they could not be distinguished using allozyme data. The endemic distribution of B. rossii (Campbell Island and Auckland Island Group) and fixed morphological differences justify its remaining a separate taxon. The formal raising of B. gibbsii var. gibbsii to a separate specific status is subject to the analysis of further samples of this taxon. B. angustifolia, B, talbotii, and B. gibbsii vat. balanifera also remain separate taxa, with B. gibbsii var. balanifera being raised to a separate specific status. B. modesta, which is genetically closely related to B. hookeri, becomes a sub-species of this taxon.</p>

The protected phosphoglucomutase polymorphism of the Pompeii worm Alvinella pompejana and its variant adaptability is only governed by two QE mutations at linked sites

The polychaete Alvinella pompejana lives exclusively on the walls of deep-sea hydrothermal vents along the East Pacific Rise. This environment is considered as extreme and highly variable and the worm displays specific adaptations to withstand high temperature and hypoxia. Previous studies revealed the existence of a balanced polymorphism on the enzyme phosphoglucomutase associated with differences in the thermal habitat of the worm. Allozymes 90 and 100 exhibited different optimal enzyme activities and thermostabilities. The exploration of the mutational landscape for allozyme variation of the phosphoglucomutase1 revealed the maintenance of four highly divergent allelic lineages that encode the three most frequent electromorphs, these alleles occurring at different frequencies in populations over the worm’s geographic range. Enzyme polymorphism is only governed by two linked amino-acid replacements located in exon 3 (E155Q and E190Q). Unlike other studies dealing with the non-synonymous variations of the Pgm genes, these substitutions are not linked to other cryptic amino-acid polymorphisms. Overdominance under specific environmental ‘hot’ conditions should represent the most likely way for the long-term persistence of these isoforms. Using directed mutagenesis, overexpression of the three recombinant variants allowed us to test the additive effect of these two mutations on the biochemical properties of this enzyme. Results are coherent with those previously obtained from native proteins and reveal a thermodynamic trade-off between the protein thermostability and catalysis, which is likely to explain the long-term selection of these functional phenotypes before their geographic separation across the Equator with the emergence of a barrier to dispersal, about 1.2 Mya.

GENETIC VARIATION IN CULTURED STOCKS OF TIGER SHRIMP (Penoeus monodon) IN INDONESIA

Three stocks of tiger shrimps, Penaeus monndon, obtained from brackish water pond culture in Aceh (Sumatera Island), Cilacap (Java Island) and Sumbawa (West Nusatenggara) were assayed for allozyme variation at 9 enzyme loci from muscle biopsies.

Allozyme variation among european beech (Fagus sylvatica L.) stands in Bosnia and Herzegovina

From the economical and ecological point of view, beech (Fagus sylvatica L.) is one of the most important forest tree species in Bosnia and Herzegovina. To understand the significance of beech forests, something about the structure of forests and forest lands needs to be said. Bosnia and Herzegovina has 3.231.500 hectares of forests and forest land, which is about 60% of its surface. In the forest and forest lands structure, we can see that it has high forest occupying 51.1% of the forest area, coppice occupying 38.70%, shrubs occupying 4%, bare land and clearings occupying 5.80% and other unproductive areas occupying 0.40%. Beech can be found in mixed stands of beech and fir, as well as stands of beech, fir and spruce that occupy 46% of all high forests. Thus, the total area of ​​forests where the beech is found is approximately 1.652.400 hectares. The aim of the study was to carry out the analysis of genetic structures of natural beech populations in Bosnia and Herzegovina by using isoenzyme markers. Conducting a biochemical genetic structure analysis of 14 beech populations, using 10 enzyme systems with 16 isoenzyme gene loci, we found significant differences. Variability in some gene loci is large, while some populations for some gene loci showed monomorphism. The results indicate that in order to maintain natural genetic resources of common beech in Bosnia and Herzegovina, there should be a dense network of gene reserves established. This network from one of the Balkan countries should then become a constituent part of all-European network. These gene banks need in situ and ex situ methods (seed banks, seed stands, and seed orchards) to maintain the genetic diversity of populations. Based on the research results, every ecological niche of common beech i.e. their genetic variation should be conserved regarding the appropriate number of populations and individuals to preserve the ecological and physiological features of this valuable commercial species.

Detecting level of genetic differentiation in two closely related species of Drosophila: D. bipectinata and D. malerkotliana

A considerable amount of allozyme variation exists among different populations of a Drosophila species. Such allozyme variation can also be observed between two closely related species of Drosophila which show reproductive isolation but experience mating under laboratory conditions and produce hybrids. D. bipectinata and D. malerkotliana are two closely related sympatric species and belong to bipectinata species complex. Allozyme polymorphism studies conducted with them and their hybrids reveal that these two species have enough genetic differentiation due to allozyme variation at three enzyme coding loci; however, their hybrids exhibit common allozyme variants of both the species. The hybrids exhibit very little genetic differentiation from either of their parents.

Allozyme variation of the endemic and vulnerable Dyera lowii Hook.f. in Central Kalimantan: Implications for genetic resources conservation

Dyera lowii is an endemic and vulnerable tree species of commercial value as chewing gum found inpeat swamp forests, scatteredly distributed in Sumatra, Kalimantan, and Peninsular Malaysia. Their existenceis now under severe threat due to habitat conversion. This study is aimed to assess genetic diversity withinfour natural populations (Hampangen, Parahangan, Sebangau, Selat Nusa ) and one plantation in CentralKalimantan based on allozyme variation. Electrophoresis procedures were conducted with an isoelectricfocusing polyacrylamide slab gel system. The result showed high genetic diversity (HE=0.52) and gene fl ow(3.402) seemed to be effective. A total of 14 alleles were found among all the analysed population. Meannumber of alleles per locus (Aa) was 3.206, and the effective number of alleles per locus (Ae) was 2.21. Geneticdifferentiation between populations (FST) was signifi cant at the moderately level (0.0685). Most allozymevariation was found within population (93.2%). Special attention is essential to conserve a private allele ofGot-1-e (9%) at Selat Nusa population. Sebangau population missed the alleles of Est-2-b and Got-1-a, as foundin other populations. Selat Nusa population is expected to enhance the effective management for geneticresources conservation of this vulnerable species in the future.