Chromosome numbers, karyotypes and nuclear DNA contents from perennial polyploid groups ofCerastium (Caryophyllaceae)

Somatic chromosome numbers have been determined for the followingCerastium taxa:C. eriophorum (2n = 36),C. alpinum (2n = 72),C. transsylvanicum (2n = 108),C. arcticum (2n = 108),C. latifolium (2n = 36),C. carinthiacum (2n = 36),C. banaticum (2n = 36),C. arvense subsp.glandulosum (2n = 36),C. arvense subsp.arvense (2n = 72) andC. fontanum (2n = 144). Karyotypes of three diploid species (C. eriophorum, C. banaticum andC. latifolium), belonging to three different taxonomic groups, were analysed and found to be similar. The relative nuclear DNA contents of all taxa were determined by flow cytometry and, for five species, also by Feulgen cytophotometry. The values obtained by the two methods are similar. A comparison of nuclear DNA contents among diploids shows that values differ significantly between different taxonomic groups, and are correlated with average chromosome size. Within closely related polyploid groups nuclear DNA amounts increase from 2x- to 4x- and 6x taxa as 1 : 1.4 : 2.4 in theC. alpinum complex, whereas DNA amounts are doubled comparing 2x- and 4x-subspecies in theC. arvense complex.     

Conifer genome sizes of 172 species,covering 64 of 67 genera,range from 8 to 72 picogram

Nuclear genome size of conifers as measured by flow cytometry with propidium iodide was investigated, striving to collect at least a single species from each genus. 64 out of 67 genera and 172 species were measured. Of the 67 genera, 21 are reported here for the first time and the same is true for 76 species. This nearly doubles the number of measured genera and adds 50% to the number of analyzed species. Conifers have chromosome numbers in the range of n = (7)10–12(19). However, the nuclear DNA content (2C‐value) is shown here to range from 8.3 to 71.6 picogram. The largest genome contains roughly 6 × 10¹⁰ more base pairs than the smallest genome. Genome sizes are evaluated and compared with available taxonomic treatments. For the mainly (sub)tropical Podocarpaceae small genome sizes were found with a 2C‐value of only 8–28 pg, with 13.5 pg on average. For the Taxaceae 2C‐values from 23–60 pg were determined. Not surprisingly, the genus Pinus with 97 species (39 species measured here) has a broad range with 2C = 38–72 pg. A factor of 2 difference is also found in the Cupressaceae (136 species) with nuclear DNA contents in the range 18–35 pg. Apart from the allohexaploid Sequoia, ploidy plays a role only in Juniperus and some new polyploids are found. The data on genome size support conclusions on phylogenetic relationships obtained by DNA sequencing. Flow cytometry is applicable even to young plants or seeds for the monitoring of trade in endangered species.     

PHYLOGENETIC ANALYSIS OF MORPHOLOGICAL SPECIES OF CARTERIA (VOLVOCALES,CHLOROPHYTA) BASED ON rbcL GENE SEQUENCES1

Four related species in the unicellular volvocalean genus Carteria [C. crucifera Pascher, C. eugametos Mitra, C. inversa (Korshikov) Bourrelly and C. cerasiformis Nozaki et al.] were delineated on the basis of recent comparative light and electron microscopy of a large number of culture strains. However, the species thus delineated may not represent natural or monophyletic entities. In the present study, 1128 base pairs of the chloroplast protein-coding gene (large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase gene) from 12 Carteria strains representing the four species as well as from related volvocalean species were analyzed to elucidate the phylogenetic status of the taxonomic or morphologic species of Carteria. The sequence data showed that the 12 Carteria strains exhibit four robust monophyletic groups which are strictly consistent with the four taxonomic species. These results are discussed in relation to contrasting results found in other microalgal genera. It is concluded that phylogenetic analysis, based on DMA sequence data and comparative morphologic characterization of species and using a large number of culture strains, is essential to a natural system of microalgal species taxonomy.     

Karyological differences among Tenebrionidae (Coleoptera)

Karyotypes obtained from spermatogonial metaphases of 20 tenebrionid species have been surveyed. The range of chromosome numbers is from 2n=16 to 2n=26, but only five species deviate from 2n=20, which is the modal and most primitive number of the family. Only the tribe Akidini shows a clear relationship between chromosome number (2n=16) and taxonomic group, while in the other species this relationship is not apparent. The mean total complement lengths in eleven species vary about twofold and the number of chromosome arms (NF) from 23 to 50. Some congeneric species ofTentyria, Hegeter andErodius displayed slight differences in the number of acrocentric chromosomes.Project number PB 87-0584-C02-01, Ministry of Education and Science, Spain     

First report of chromosome numbers and karyotypes of two monotypic genera endemic to eastern Asia: Brachystemma (Caryophyllaceae) and Craspedolobium (Fabaceae)

The chromosome numbers and karyotypes of Brachystemma and Craspedolobium, two monotypic genera endemic to eastern Asia, are reported here for the first time. The somatic chromosome numbers are 2n=40 for Brachystemma calycinum and 2n=22 for Craspedolobium unijugum. A karyotype of 2n=2x=40=28m+12sm was found in B. calycinum and that of 2n=2x=22=12m+10sm in C. unijugum, both of them have a moderately symmetrical karyotype type 2B and small‐sized chromosomes. Brachystemma has a unique basic chromosome number in Alsinoideae, which may support its isolated taxonomic position. As do some morphological characters, the basic chromosome number x=11 suggests that Craspedolobium belongs in the Millettioid clade.     

Systematics of the species of the yeast genus Saccharomyces associated with the fermentation industry

Summary The so-called wine yeasts Saccharomyces cerevisiae, S. chevalieri, S. bayanus, S. italicus and S. uvarum are characterized by high ethanol tolerance and fermentation velocity. They are ecologically related, being predominantly associated with grape must and wine, and are taxonomically indistinguishable. The only significant physiological differences are between the ability to ferment certain sugars. A taxonomic revision of more than 1,000 strains isolated during the past 50 years and belonging to the above species showed extreme instability in the ability to ferment different sugars. The relationships between these yeasts were examined for DNA base composition and DNA-DNA reassociation. The G+C ranged from 37.6% to 39.0% while optical reassociation experiments defined a first group of species (Saccharomyces cerevisiae, S. chevalieri and S. italicus) exhibiting high base sequence complementarity (>90%). S. bayanus and S. uvarum also showed a high degree of relatedness. Low homology values (30%) indicate that the two groups of species are not closely related. While it is proposed to combine S. cerevisiae, S. chevalieri and S. italicus into one single species under the oldest epithet Saccharomyces cerevisiae, a study of a larger number of strains is recommended before considering the taxonomic position of S. bayanus and S. uvarum.     

Genome size variation and species relationships in the genus Hydrangea

Genome size and base composition in 16 species and subspecies of the Hydrangea, a woody ornamental genus of Hydrangeaceae, were evaluated by flow cytometry in relation to their chromosome number. This is the first such study concerning the genome size of these species together with a karyotype study of the most important species, Hydrangea macrophylla subsp. macrophylla (Hortensia), from an economical point of view. The 2C DNA content ranged from 1.95 pg in Hydrangea quercifolia to 5.00 pg in Hydrangea involucrata. The base composition ranged from 39.9% GC in Hydrangea aspera subsp. sargentiana to 41.1% in Hydrangea scandens subsp. scandens (significant difference at p < 0.05). The smallest genome sizes were those of the three species originating from North or South America. Most of the species studied presented a chromosome number of 2n = 2x = 36, except for those of the section Aspereae which showed 2n = 30, 34 and 36. A primary karyotype has been made for the first time for H. macrophylla subsp. macrophylla. Phylogenetic relationships between species, the origin of chromosome number and an exploration of the genetic diversity within the genus are discussed. Received: 24 July 2000 / Accepted: 31 October 2000     

CHROMOSOME NUMBERS IN CUPHEA (LYTHRACEAE): NEW COUNTS AND A SUMMARY

The American genus Cuphea with ca. 260 species is extremely diverse with respect to chromosome number. Counts are now available for 78 species and/or varieties, or 29% of the genus. Included in this study are first reports for 15 taxa from Brazil, Cuba, Dominican Republic, Mexico, and Venezuela. Twenty-two different numbers are known for the genus, ranging from n = 6 to n = 54. The most common number in the primary center of species diversity in Brazil is n = 8, which is regarded as the base number of the genus. Two numbers are most common in the secondary center in Mexico, n = 10 and n = 12. Species with n = 14 or higher are considered to be of polyploid origin. Polyploids comprise 46% of the total species counted and appear in 9 of the 11 sections for which chromosome numbers have been reported. Aneuploid species comprise ca. 25% of the genus and are known from 7 of the 11 sections. The two subgenera are not characterized by different chromosome numbers or sequences of numbers. None of the 14 sections are circumscribed by a single chromosome number. Morphological and ecological variability in widespread, weedy species is correlated with differing chromosome numbers in some species whereas in others the chromosome number is stable. Summary of chromosome numbers by taxonomic section is presented. Section Euandra, centered in eastern Brazil, and the largest section of the genus, appears to be chromosomally most diverse. In section Trispermum, characterized by difficult, variable species with intermediate forms, two of the four species studied have polyploid races. Section Heterodon, endemic to Mexico and Central America and comprising most of the annual species of the genus, is best known chromosomally. Chromosome numbers have been counted for 25 of 28 species, and 12 different numbers are reported. The most advanced sections, Melvilla and Diploptychia, with numerous species occurring at higher altitudes, are characterized by high polyploids. Apomictic species occur in sect. Diploptycia. The cytoevolution of Cuphea is complex with frequent polyploid and aneuploid events apparently playing a significant role in speciation in both centers of diversity.     

New insights on systematics and phylogenetics of Mediterranean Blaps species (Coleoptera: Tenebrionidae: Blaptini), assessed through morphology and dense taxon sampling

The genus Blaps is an emblematic group of large flightless beetles adapted to semi‐arid and arid environments. About 230 species have been described in the subgenus Blaps, which is the largest of the four extant subgenera. Within this subgenus, one large group of morphologically homogeneous species is of particular interest, and comprises the species formerly assigned to Seidlitz's division one. Strikingly, almost all species in this group are endemic to the Mediterranean basin, whereas the remaining Blaps species are mostly distributed in Asia. Here we present the first phylogenetic hypothesis for the Mediterranean Blaps and several taxonomic clarifications for the North African species belonging to this group. Based on careful examination of almost all type material and thousands of specimens for all known species and subspecies (initially 65 taxa), seven lectotypes are designated and six new synonymies are established: Blaps heydeni Allard, 1880 = Blaps heydenissp. taciturna Peyerimhoff syn.n. , Blaps emondi Solier = Blaps nitidula Solier syn.n. , Blaps tripolitanica Karsch = Blaps vialattei Peyerimhoff syn.n. , Blaps bifurcata strauchi Reiche = Blaps bifurcata ssp. gridellii Pierre syn.n. , Blaps cognata Solier = Blaps schweinfurhtii Seidlitz syn.n. and Blaps judaeorum Miller = Blaps pharao Seidlitz syn.n. Among the examined material, five species are also new for science and are assigned to extant species group. To infer species relationships, a morphological character matrix was assembled and analysed using both parsimony and probabilistic methods. All analyses yielded a similar and repeatable phylogenetic pattern, which allows us to discuss the systematics of the Mediterranean endemic species, the limit of extant species groups and to clarify the taxonomic status of several ambiguous taxa. We also reveal the existence of a large clade that encompasses the eastern Mediterranean species that are also mostly associated with arid regions. This clade is embedded within a second group that corresponds to western Mediterranean species, which are generally found in semi‐arid regions. Finally, we discuss the relevance of species groups in relation to their geographic distribution. This work represents a first step for further studies in taxonomy, systematics and historical biogeography of Blaps species.     

The annual species ofAdonis (Ranunculaceae)—a polyploid complex

The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.     

Karyotype studies in thirty‐two species of Lilium (Liliaceae) from China1

Fifty‐two populations representing thirty‐two taxa of Lilium L. from China are karyologically analyzed. The results showed that all populations have the same basic chromosome number x=12, and all species are diploid except Lilium tigrinum, which is triploid with 2n=36. In addition, one population of L. sulphureum is aneuploid with 2n=23. The karyotype evolution in the genus Lilium is mainly in terms of alterations of the fine structure of the chromosomes, not in ploidy or basic chromosome number variation. When combining previous studies and our results, we consider the major driving forces for evolution of Lilium to be an increase in karyotypic asymmetry, and unequal translocation and formation of secondary constrictions. The existence of intercalary satellites on the two largest pairs of chromosomes is correlated with the geographic distribution pattern of Lilium across the world. The Hengduan Mountains is a modern diversity and differentiation center of Lilium and it also could be the center of origin for this genus. In addition, some taxonomic conclusions were verified on the subgenus level. Among the species investigated, the chromosome number and karyotypes of 13 taxa were documented for the first time.     

Chromosomes of thecercopithecus aethiops species group:C. aethiops (Linnaeus, 1758),C. cynosurus (Scopoli, 1786),C. pygerythrus (Cuvier, 1821), andC. sabaeus (Linnaeus, 1766)

The banded karyotypes of 34 monkeys of known geographic origin and belonging to the Cercopithecus aethiops group of species (C. aethiops, C. pygerythrus, C. cynosurus, C. sabaeus) show that chromosome evolution in this group is highly conservative. All species have 2n =60 chromosomes with very similar chromosome banding. However, differences were found both within and between species. A polymorphism of the NOR area of the “marked” chromosome pairs was found in all taxa (9 of 34 animals). All individuals referred to C. sabaeus,from both West Africa and the Barbados, are characterized by having highly positive G- and C- banded terminal sequences on chromosomes 7,10,12, and 14. Outgroup comparisons with other primates and a parsimony analysis suggest that these terminal bands are derived and are probably good taxonomic and phylogenetic indicators. Moreover, chromosome 18 is variable both between and within species in G banding and in short-arm length. The existence of within-species variation in karyotypes suggests that karyological comparisons must be based on adequate samples that include specimens coming from all the major geographic populations of the species concerned.     

Karyology of Aconitum subgenus Lycoctonum (Ranunculaceae) from China,with a report of the new base chromosome number x = 6 in the genus Aconitum

In order to gain better knowledge of the number and morphology of chromosomes in Aconitum subgen. Lycoctonum in China, 60 populations belonging to 20 species were cytologically studied. Chromosome numbers of six species (A. apetalum, A. finetianum, A. fletcheranum, A. longecassidatum, A. umbrosum and A. wangyedianense) are here reported for the first time. One species, A. fletcheranum, has 2n = 12, and thus is a diploid based on x = 6, a new base chromosome number for the genus Aconitum. Most of the remaining taxa are diploid (2n = 16) based on x = 8, but five taxa (A. angustius, A. brevicalcaratum var. brevicalcaratum, A. brevicalcaratum var. parviflorum, A.chrysotrichum and A. crassiflorum) are tetraploid with 2n = 32, and one species (A. apetalum) is hexaploid with 2n = 48, the highest ploidy level currently known in the subgenus. Disregarding differences in the presence or absence and number of satellites, the karyotypes of all the 2n = 16 species are quite uniform (2n = 2m + 6sm + 8st), but A. novoluridum, the only species of A. section Alatospermum, has an intrachromosomally less asymmetric karyotype (2n = 2m + 14sm), which lends further support for the primitive condition of its section as inferred from gross‐morphology. Chromosomal variation in the subgenus and the relationships of some of the species are discussed.     

Karyological studies in someHypochoeris spp. (Compositae) from Sicily

FiveHypochoeris spp. from Sicily have been investigated:H. glabra L. (2n=10),H. radicata L. (2n=8),H. cretensis L. (2n=6),H. laevigata L. (2n=12),H. robertia Fiori (2n=8). Basic chromosome numbers are very variable, x = 3, 4, 5, 6. The karyotype of each species is presented. Geographical origin (S. America or Mediterranean region) of the genusHypochoeris and the taxonomic position ofH. robertia are discussed.     

Nonea dumanii sp. nov. (Boraginaceae) from the Taurus mountains (south Turkey)

The new species Nonea dumanii, endemic to the mountains of the western Taurus in south Turkey (C4 Antalya), is described an illustrated based on original collections by the authors. Karyological observations and analysis of ITS1 DNA sequences showed that the species is probably hexaploid with 2n = 6x = 60 and has phylogenetic affinity to the diploid N. monticola from the Paphlagonian mountains as well as to the tetraploid N. anchusoides from northwest Iran and southeast Turkey. From these allopatric species it is morphologically distinct in characters of the indumentum, flower and fruit. Polyploidy is supported as a major driving force for speciation in Nonea, especially in the group of Anatolian mountain species with primary base number x = 10.     

Karyotypes of the Echinogammarus berilloni-group (Crustacea,Amphipoda) from Spain

The chromosome number and karyological features of Iberian populations of seven species of the Echinogammarus berilloni-group (Crustacea, Amphipoda) have been studied. For comparison, Gammarus gauthieri, belonging to the G. pulex-group was also studied. Four species of the berilloni-group share the same number n=27. Other numbers found were n=25, n=26 and n=28. The chromosomes of these species have a centromeric region surrounded by large heterochromatic blocks at late prophase. There-after, the centromere splits precociously. C. gauthieri has n=26, the same number found in the pulex-group. This species has larger chromosomes than the former but it does not show these karyological peculiarities.Cytological observations confirm both the close relationship among species of the berilloni-group and the differentiation with respect to the pulex-group. On the other hand, the existence of different numbers confirms other results that reject the older idea that speciation within Gammaridea occurred with minor changes in karyotypic characters.     

CHROMOSOME NUMBERS IN THE PHASEOLEAE (FABACEAE:FABOIDEAE) AND THEIR RELATION TO TAXONOMY

Chromosome numbers are reported for 33 species of the tribe Phaseoleae. Six reports are first counts for their species; one report (Ophrestia hedysaroides) is a first count for the genus. This increases the number of genera counted to 53 out of a total 84 for the tribe. A survey of base numbers shows a general pattern of numbers 10 or 11, the same base numbers as in the neighboring tribes Dalbergieae sensu lato, Galegeae sensu lato, and Abreae. The chromosomes are generally small and polyploidy is uncommon. Deviations from base numbers 10 or 11 are mostly found in those genera with morphological pecularities and puzzling taxonomic placements: Erythrina (21), Clitoria (8, 11, 12), Butea (9), Calopogonium (18), Teramnus (14), and Strongylodon (14). Two genera have base numbers which suggest derivation by polyploidy: Glycine (20) and Cologania (22).     

The cytology of Brachycome lineariloba

A study of approximately 300 plants in the taxonomic species B. lineariloba is reported. Five biological species differing in chromosome number exist in this species complex. The species with the lowest number (species A, n = 2) often carries B chromosomes, which may be large, or minute. It also exists in three racial forms which differ in karyotype. Observations on naturally occurring hybrids in zones of overlap show that two of the races differ by an unequal interchange. — The species with n = 8 (species C) is probably of amphidiploid origin from the cross A X B. Species B, E and D, with n = 6, 5 and 4 respectively, may represent a series of reductions in chromosome number. They show close karyotypic relationships. The relationship of species A with D, E and B is obscure.