The DNA content of blood cell nuclei of 15 species of cranes was determined by Feulgen-DNA cytophotometry. Genome sizes agree with values reported elsewhere for several crane species analyzed by flow cytometry. Males have more DNA per cell than females in several species. A karyotype where 2n = 80 is reported for a male greater sandhill crane.

The variability of the genome size reaches several grades even within relatively close groups of plants. The study of the genome size in the phylogenetic context provides interesting results which characterize the evolution of the individual groups of plants. In this respect, tropical plants have yet not been studied. Tropical genus Globba (ca. 100 species) belongs to an economically significant family Zingiberaceae. The diversity centre is found in Thailand but it spreads from east India and southern China up to Indonesia and the Philippines. It is a polyploid complex which exists in two cytotypes within one genus (2n = 32 a 2n = 48); it is characteristic minimally in three out of seven distinguished sections. The aim of this thesis has been a reconstruction of the group phylogeny, discovering the role of the polyploid and evaluation of the genome size evolution of the Globba genus in the phylogenetic context. To this end, modern biosystematic methods were used (flow cytometry, chromosome counting, sequencing of the nuclear and chloroplast DNA regions). Many types of software and statistical methods were used to process and interpret the data. In this group, the genome size was measured for the first time. Out of 87 individuals, the smallest size was measured with Globba nuda (2C = 1.11 pg). The...

This thesis concerns genomic variation within the Annelida, for which genome size studies are few and provide data for only a handful of groups. Genome size estimates were generated using Feulgen image analysis densitometry for 35 species of leeches and 61 polychaete species. Relationships were explored utilizing collection location and supplementary biological data from external sources. A novel, inverse correlation between genome size and maximum adult body size was found across all leeches. Leeches that provide parental care had significantly larger genome sizes than leeches that do not. Additionally, specimens identified as Nephelopsis obscura exhibited geographic genome size variation. Within the Polychaeta, Polar region polychaete genomes were significantly larger than those of Atlantic and Pacific polychaetes. These studies represent the first exploration of leech genome sizes, and provide base evidence for numerous future studies to examine relationships between genome size and life history traits across and within different annelid groups.

Adult somatic nuclear DNA contents are reported for eleven cyclopoid species (Megacyclops latipes, Mesocyclops edax, M. longisetus, M. ruttneri, M. leuckarti, M. woutersi, Macrocyclops albidus, Cyclops strenuus, Acanthocyclops robustus, Diothona oculata, Thermocyclops crassus) and for the harpacticoid Tigriopus californicus and range from 0.50 to 4.1 pg DNA per nucleus. These diploid genome sizes are consistent with previously published values for four Cyclops species (0.28-1.8 pg DNA per nucleus), but are strikingly smaller than those reported for marine calanoids (4.32-24.92 pg DNA per nucleus). We discuss three explanations, none of them exclusive of another, to account for the smaller size and range of cyclopoid genome sizes relative to calanoid genome sizes: (1) higher prevalence of chromatin diminution in the Cyclopoida, (2) phylogenetic structure or older age of the Calanoida relative to Cyclopoida and (3) nucleotypic selection that may influence life history variation and fitness. Measurements of genome size were made on Feulgen stained, somatic cell nuclei, using scanning microdensitometry which is well suited to the sparse and heterogeneous populations of copepod nuclei. The importance of measuring large numbers of nuclei per specimen, possible sources of variation associated with cytophotometric measurements, and appropriate use of internal reference standards and stoichiometry of the Feulgen stained nuclei are discussed.

Genome sizes for 36 species of cyclopoid copepods were determined by DNA-Feulgen cytophotometry of nuclei from adults collected from diverse habitats and locales in North America, South America, Europe, and Asia. Genome sizes are small, show a 20-fold range (C = 0.10-2.02 pg DNA), and vary in a discontinuous fashion. The genomes of cyclopoid copepods are remarkably small and constant within each species, unlike the large and variable genomes of marine calanoid species. These differences may reflect the evolutionary antiquity of marine copepods in relation to marine, brackish, and freshwater copepods, as well as differences in mechanisms used to modulate genome size. The small genome sizes of contemporary cyclopoids provide substantive evidence of evolutionary constraint, possibly favouring small genomes, rapid replication rates and accelerated development as adaptive strategies for survival in often fragmented, stressful, and changing habitats.

Lake Baikal in Russia is a large, ancient lake that has been the site of a major radiation of amphipod crustaceans. Nearly 400 named species are known in this single lake, and it is thought that many more await description. The size and depth of Lake Baikal, in particular, may have contributed to the radiation of endemic amphipods by providing a large number of microhabitats for species to invade and subsequently experience reproductive isolation. Here we investigate the possibility that large-scale genomic changes have also accompanied diversification in these crustaceans. Specifically, we report genome size estimates for 36 species of Baikal amphipods, and examine the relationship between genome size, body size, and the maximum depths at which the amphipods are found in the lake. Genome sizes ranged nearly 8-fold in this sample of amphipod species, from 2.15 to 16.63 pg, and there were significant, positive, phylogenetically corrected relationships between genome size, body size, maximum depth, and diversification rate among these species. Our results suggest that major genomic changes, including transposable element proliferation, have accompanied speciation that was driven by selection for differences in body size and habitat preference in Lake Baikal amphipods.

Penstemon is the largest genus in North America with more than 270 reported species. However, little is known about the genome size of this genus and how this information may be useful in selecting species in developing hybrids for landscape use. Using flow cytometry, we estimated the genome size of approximately 40% of the genus (117 specimens from 104 different species.) Genome sizes for the putative diploids ranged from 2C = 0.94 – 1.89 pg (1C = 462 – 924 Mbp) and the putative polyploids ranged from 2.57 – 6.54 pg (1C = 1,257 – 3,156 Mbp). Chromosome counts were compiled and compared with the flow cytometry results for the species within this publication. Ploidy within the genus ranged from diploid to dodecaploid. These data were compared and contrasted with the current taxonomy of Penstemon and previously published ITS and cpDNA phylogenetic work. Based on genome size, reassigning P. montanus, P. cardinalis, and P. uintahensis to the subgenus Penstemon and P. personatus to the subgenus Dasanthera, would better reflect the phylogeny of the genus. Both auto- and allo-polyploidization are plausible mechanisms for increasing ploidy within the genus. The diploid species within the subgenus Saccanthera contain on average 1.09 pg (1C = 532 Mbp); however, two species within this subgenus are tetraploid and octaploid. The DNA content of subgenus Penstemon exhibits high plasticity and spans a six-fold increase. Our study found flow cytometry to be useful in species identification and verification. This represents the first published work on the genome size of Penstemon. This research will aid in future DNA sequencing experiments and breeding programs.

タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1996 (平成8)年度

Genomic analysis provides a substantial amount of information on evolutionary history, novel genes, transcriptomic expression and regulation in response to environmental stimuli, how efficiently organisms utilize their genome, and directional genome evolution. Genome size analysis serves as the first step in the sequencing process, because sequencing and annotation costs are directly correlated with genome size. Invertebrates represent the vast majority of faunal diversity on the planet, and, to a greater extent, the marine environment, although they are vastly understudied when compared to vertebrate genomes. Flow cytometry is a widely used, reliable, and accurate means of estimating genome sizes and has yielded valid measurements in this comparatively broad taxonomic study. This methodology quantifies genome sizes by measuring the fluorescent re-emission from nuclei that have been saturated with DNA- intercalating dyes, such as propidium iodide. Genome sizes of 19 species across five phyla were estimated by comparison with the known genome size of chicken (Gallus domesticus). Several estimates reported here are the first for their species or class. In addition to estimating new marine invertebrate genome sizes, analyses of some common preservation methods of tissue viability for flow cytometric estimations were performed. Generally, in comparison to RNAlater or ethanol, DMSO-based storage buffer was most successful at preserving nuclear membrane integrity, a requirement for flow cytometric genome size estimations. Recommendations of cost-effective species eligible for current next-generation sequencing technology (<3.5 Gb) are given for invertebrate genomicists seeking potential novel species to sequence.

Genome size or nuclear DNA content is a a trait which varies greatly among living organisms, with no apparent relashionship between genome size and organismal complexity. It is usually described using the C-value as either a number of base pairs or picograms of DNA. Unresolved questions regarding mechanisms influencing genome size and relationships between genome size and other organismal traits are together known as the C-value enigma. Genome size is known to positively correlate with cell size and negatively with developmental and cell division rate. A maximum constraint of 2 pg has also been proposed for haploid genome sizes of holometabolous insects. Despite the fact that there are about one million described insect species, genome sizes are only known in a fraction of them. This thesis thus aims to extend the dataset of known insect genome sizes by as many species of cockroaches (Blattodea) as possible. Another aim is to compare results with known phylogeny and also to compare difference in genome size between sexes. Flow cytometry was used for genome size estimations, which is a rapid, simple and effective method, also suitable for study of ploidy levels and other cellular charasteristics.