Publications by authors named "AE Szmidt"

Pinus krempfii Lecomte is a morphologically and ecologically unique pine, endemic to Vietnam. It is regarded as vulnerable species with distribution limited to just two provinces: Khanh Hoa and Lam Dong. Although a few phylogenetic studies have included this species, almost nothing is known about its genetic features.

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Distribution of tropical rainforests in Southeastern Asia has changed over geo-logical time scale, due to movement of tectonic plates and/or global climatic changes. Shorea parvifolia is one of the most common tropical lowland rainforest tree species in Southeastern Asia. To infer population structure and demographic history of S.

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The Andricus mukaigawae complex of oak gall wasps is composed of cyclically parthenogenetic species: A. mukaigawae and Andricus kashiwaphilus, and a parthenogenetic species, Andricus pseudoflos. The component species differ in life history, host plant, karyotype, and asexual gall shape, although little difference is found in the external morphology of asexual adults.

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In mangrove species the past geomorphic changes in coastal regions and reproductive systems are important factors of their distribution and genetic structure of populations. However, very little is known about the levels of genetic variation of Rhiozophora species in Southeast Asia. In this study, we surveyed levels and patterns of genetic variation as well as population structure of two sympatric mangrove species, Rhizophora apiculata and R.

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Allothrombium pulvinum Ewing is a common natural enemy of aphids and some other arthropods. So far, there are no studies that have addressed genetic variation of this predatory mite. We investigated genetic variation of A.

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Larch (Larix Mill.) is one of the most widely distributed tree genera in Eurasia. To determine population structure and to verify classification of five species and three varieties of the Eurasian Larix species, we investigated levels and patterns of nucleotide variation of two nuclear gene regions: the 4-coumarate coenzyme A ligase (4CL) and the coumarate 3-hydroxylase (C3H).

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Dipterocarpoideae, the largest sub-family of well-known plant family Dipterocarpaceae, dominates in South Asian rain forests. Although several previous studies addressed the phylogeny of the Dipterocarpaceae family, relationships among many of its genera from the Dipterocarpoideae sub-family are still not well understood. In particular, little is known about the relationships of the genera Vateriopsis, Stemonoporus, Vateria and inconsistence remains between phylogenetic results and taxonomic classifications of Shorea and Hopea species.

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Although homoploid hybridization is increasingly recognized as an important phenomenon in plant evolution, its evolutionary genetic mechanisms are poorly documented and understood. Pinus densata, a pine native to the Tibetan Plateau, represents a good example of a homoploid hybrid speciation facilitated by adaptation to extreme environment and ecological isolation from the parents. Its ecologically and reproductively stabilized nature offers excellent opportunity for studying genetic processes associated with hybrid speciation.

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In natural populations of Drosophila melanogaster, there are many amylase (AMY) isozymes encoded by the duplicated genes, but their adaptive significance remains unclear. One approach to elucidate this issue is to understand the molecular basis of functional differences between the allelic classes. In this study, the effects of nucleotide polymorphism in 5'-flanking (cis-regulatory) and coding regions on AMY activity were examined, both on glucose and starch food media and in larvae and adults, using three chimeric Amylase (Amy) genes, Amy(c111), Amy(c161) and Amy(fc661).

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We examined levels and patterns of nucleotide variation in 21 strains of Drosophila kikkawai from Miyako island, Japan for the partial regions of the following seven nuclear genes: Adh, Ddc, esc, ksr, Pgi, su(f), and Tpi. The nucleotide variation at total sites (pi(t)) ranged from 0.0013 in the ksr, to 0.

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We compared the genetic variation of Pinus pinaster populations using amplified fragment length polymorphism (AFLP) and chloroplast simple-sequence repeat (cpSSR) loci. Populations' levels of diversity within groups were found to be similar with AFLPs, but not with cpSSRs. The high interlocus variance associated with the AFLP loci could account for the lack of differences in the former.

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Pinus densata has been suggested to have originated from hybridization events involving P. tabulaeformis and P. yunnanensis.

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The chloroplast trnS-psbC gene regions from total genomic DNA of 119 accessions from seven small millet species were amplified by polymerase chain reaction (PCR) and digested with eight restriction enzymes individually as well as in combinations of two enzymes to generate restriction fragment length polymorphism (PCR-RFLP). PCR-RFLP with individual enzymes revealed polymorphism between only some species. However, all the species could be distinguished by using a combination of two enzymes, specifically HaeIII and MspI.

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The sequence divergence of chloroplast rbcL, matK, trnV intron, and rpl20-rps18 spacer regions was analyzed among 32 Pinus species and representatives of six other genera in Pinaceae. The total aligned sequence length is 3570 bp. Of the four sequences examined, matK evolved much faster than rbcL in Pinus and in other Pinaceae genera.

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We analysed the properties of AFLP markers in Pinus sylvestris. Using primers with three selective nucleotides, the AFLP protocol produced large numbers of amplified bands and could only be used with a restricted number of primer combinations. Replacement of the EcoRI +3 primer by an EcoRI +4 primer halved the number of bands, facilitating analysis.

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Sequence analysis of the mitochondrial coxI gene in eight gymnosperm species revealed a high rate of nonsynonymous nucleotide substitutions with a strong (98%) predominance of C-T substitutions. Further analysis of the corresponding coxI cDNA sequences showed that all the non-synonymous C-T changes in the coxI genomic DNA sequences were eliminated by RNA editing resulting in nearly identical mRNA (amino acid) sequences among the species. Pronounced variation in the number and location of edited sites was found among species.

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We studied allozyme and chloroplast (cp) DNA variation in natural populations of Pinus kesiya and P. merkusii from Thailand and Vietnam. The results showed striking differences between the two species in the amount and distribution of allozyme variation.

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The structure and variation of nuclear ribosomal DNA (rDNA) units of Picea abies, (L.) Karst. was studied by restriction mapping and Southern hybridization.

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Heterologous hybridization of chloroplast DNA (cpDNA) involving 30 endonucleaseprobe combinations was used to analyze cpDNA variation in multiple individuals and populations of Pinus tabulaeformis (Carr.), Pinus yunnanensis (Franchèt) and Pinus massoniana (Lamb.).

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Allozyme variation was examined in 22 populations of Pinus densiflora (Sieb, et Zucc.) and four geographic varieties of P. sylvestris (L.

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Restriction fragment analysis and heterologous hybridization of chloroplast (cp) DNA was used to develop species-specific markers for P. tabulaeformis, P. yunnanensis and P.

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Allozyme differentiation at 13 loci was studied in populations of Pinus tabulaeformis, P. densata, and P. yunnanensis from China.

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Chloroplast DNA (cpDNA) restriction analysis was used to classify five reforestation seedlots as to species. The material included two Sitka spruce (Picea sitchensis (Bong.) Carr.

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Chloroplast DNS from species of five different conifer genera was extracted and studied by Southern blot analysis. For all these species, hybridization with heterologous probes specific for 16 S and 23 S rDNA detected only one chloroplast DNA fragment per enzyme digest. This observation suggests that the 16 S and 23 S rRNA genes are not duplicated in these genomes.

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Restriction enzyme analysis was used to determine the inheritance of chloroplast DNA in conifers. The plant material studied included five individual trees of European larch (Larix decidua Mill.) and Japanese larch (Larix leptolepis Sieb.

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