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841.
MAGED MAHMOUD ABOU-EL-ENAIN 《Botanical journal of the Linnean Society. Linnean Society of London》2002,139(4):409-414
Chromosome numbers and measurements were recorded in 22 individuals from six populations of six species of Onobrychis , including the Egyptian species and most representatives of section Lophobrychis . The basic number of chromosomes was either x = 7 or x = 8 and the chromosomes were medium to medium-small, ranging in length, from c . 1.6 μm to 2.6 μm. Two new ploidy levels were found, 2 n = 4 x = 28 in O. bobrovii Grossh. and 2 n = 4 x = 32 in O. pulchella Schrenk. The origin of the chromosome numbers, geographical distribution and evolution of the species were assessed. Comparison of the data with those in the literature revealed that the observed interspecific variability among section Lophobrychis can be useful in taxonomic delimitation and demonstrates a complexity of evolution between the diploid and polyploid species. Section Lophobrychis has a comparatively highly derived organization and can be considered as a heterogeneous unit in the genus Onobrychis . © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 409–414. 相似文献
842.
843.
Eight species of Ophrys sect. Pseudophrys (Orchidaceae) were cytogenetically studied. The analysed species possess the most symmetrical karyotypes of the genus (MCA ranged from 10.21 to 15.87 and CVCL from 19.61 to 23.93) with 2n = 2x = 36, being composed of mainly metacentric chromosomes. The karyotype formulae were: 36m for Ophrys archimedea, 32m + 4sm for O. flammeola, 32m + 4sm for O. funerea, 36m for O. laurensis, 36m for O. lojaconoi, 34m + 2sm for O. lucifera, 34m + 2sm for O. obaesa and 36m for O. pallida. Karyotype morphometric characters were evaluated by calculating MCA and CVCL for the assessment of karyotype asymmetry, and CVCI for the evaluation of heterogeneity in the position of the centromeres. The relationships between species were thus finally elucidated. The species characterised by wide distribution show greater karyomorphological distance than those with restricted distribution. The possible evolutionary role of chromosomal rearrangements as well as gene mutations in the speciation of Ophrys is discussed. 相似文献
844.
The life history of Ilybius fenestratus was studied in Målsj?en, a lake in S?r-Tr?ndelag, Central Norway (63°14'N, 10°26'E), during 1971–1972. Adults and larvae were sampled in activity traps every week during March–October and every 2–3 weeks during November–February. Newly-emerged adults were generally found from mid-July to September, and after overwintering in torpidity, probably in the water, they again appeared in the second half of June to August/September. Laying of eggs took place from early/mid July to early August. Larvae occurred in the traps from late July to early May. I. fenestratus was thus found to be a semivoltine summer breeder, with overwintering larvae the first winter and overwintering adults the next. Both adults and larvae lived in large areas of the lake's littoral zone. 相似文献
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847.
LIDIA POGGIO GRACIELA GONZÁLEZ CARLOS A. NARANJO † 《Botanical journal of the Linnean Society. Linnean Society of London》2007,155(2):171-178
This paper presents the karyotype and DNA content of 12 diploid species of Hippeastrum from South America. The variation in genome size is compared with the karyotype and DNA content of Amaryllis belladonna from South Africa. The Hippeastrum species present a uniform and bimodal basic karyotype formula, but significant differences are found in the total chromosome volume (TCV) and nuclear DNA content. A positive correlation between the DNA content and TCV is also observed. The karyotype's constancy is a product of changes in DNA content occurring in the whole chromosome complement. The DNA addition to the long and short sets of chromosomes varies independently. In species with higher DNA contents, the short chromosomes add equal DNA amounts to both arms, maintaining their metacentric morphology, whereas the long chromosomes add DNA only to the short arm, increasing the chromosome symmetry. These data show that the evolutionary changes in DNA amount are proportional to chromosome length, maintaining the karyotypic uniformity. A. belladonna has a larger DNA content and possesses a karyotype different from that of Hippeastrum spp., supporting the distinction between the two genera and upholding the name Amaryllis for the South African entity against Hippeastrum for the South American genus. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 171–178. 相似文献
848.
849.
Awit Suwito Masanori J. Toda Hisaki Takamori Kaori Harada Hideaki Watabe 《Entomological Science》2014,17(1):75-85
A new species of the Drosophila (Drosophila) melanica species group (Diptera: Drosophilidae), Drosophila denruoi Suwito & Watabe, sp. nov., is described from northern Vietnam. It is proved by crossing experiments that reproductive isolation is complete between this species and other morphologically similar species. Larval ganglion cells of D. denruoi possess 2n = 12 chromosomes, comprised of four pairs of acrocentric, one pair of metacentric and one pair of micro‐chromosomes. This is the largest number of acrocentric chromosomes in the group and implies that the species has the most primitive chromosomal configuration in the melanica group. Based on the results of crossing experiments and close morphological examination, Drosophila pengi Okada & Kurokawa, 1957 from central Japan, once regarded as a synonym of Drosophila tsigana Burla & Gloor, 1952, is shown to be distinct from D. tsigana. Drosophila pengi is thus resurrected as a member of the melanica group. We synonymize Drosophila bisetata Toda, 1988, described from central Myanmar, with D. pengi. In addition, a population from Guizhou, southwestern China, once regarded as D. tsigana, is also identified as D. pengi. These populations from central Myanmar and southwestern China share the diagnostic characters of D. pengi. At the same time, it is reconfirmed that the Hokkaido population is conspecific with European D. tsigana. Furthermore, another species, Drosophila longiserrata Toda, 1988 described from central Myanmar, is synonymized with Drosophila afer Tan, Hsu & Sheng, 1949 from China, based on their having identical karyotypes and external morphology. 相似文献
850.
Fabilene Gomes Paim José Henrique Souza Galdino Brand?o Iracilda Sampaio Paulo Roberto Antunes de Mello Affonso Débora Diniz 《Genetics and molecular biology》2014,37(4):646-651
Parrotfishes (Labridae, Scarinae) comprise a large marine fish group of difficult identification, particularly during juvenile phase when the typical morphology and coloration of adults are absent. Therefore, the goal of this study was to test cytogenetic markers and DNA barcoding in the identification of bucktooth parrtotfish Sparisoma radians from the northeastern coast of Brazil. Sequencing of cytochrome c oxidase subunit I (COI) confirmed all studied samples as S. radians, and all showed high similarity (99–100%) with Caribbean populations. The karyotype of this species was divergent from most marine Perciformes, being composed of 2n = 46 chromosomes. These consisted of a large number of metacentric and submetacentric pairs with small amounts of heterochromatin and GC-rich single nucleolar organizer regions (NORs) not syntenic to 5S rDNA clusters. These are the first data about DNA barcoding in parrotfish from the Brazilian province and the first refined chromosomal analysis in Scarinae, providing useful data to a reliable genetic identification of S. radians. 相似文献