Chromosomal Differentiation in Bitterlings (Pisces, Cyprinidae)

2007 ◽  
pp. 3-16 ◽  
Author(s):  
Takayoshi Ueda
Keyword(s):  
Chromosomal Differentiation

scholarly journals Chromosomal differentiation in Podisma pedestris: a third race

Heredity ◽  
1988 ◽  
Vol 61 (1) ◽  
pp. 149-157 ◽  
Author(s):  
J Gosálvez ◽  
J L Bella ◽  
G M Hewitt
Keyword(s):  
Chromosomal Differentiation

Genic and Chromosomal Differentiation in Pocket Gophers of the Geomys bursarius Group

Evolution ◽  
1974 ◽  
Vol 28 (4) ◽  
pp. 557 ◽  
Author(s):  
Robert K. Selander ◽  
Donald W. Kaufman ◽  
Robert J. Baker ◽  
Stephen L. Williams
Keyword(s):  
Pocket Gophers ◽  
Chromosomal Differentiation ◽  
Geomys Bursarius

scholarly journals Chromosomal Differentiation in Genetically Isolated Populations of the Marsh-Specialist Crocidura suaveolens (Mammalia: Soricidae)

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 270 ◽  
Author(s):  
Francisca Garcia ◽  
Luis Biedma ◽  
Javier Calzada ◽  
Jacinto Román ◽  
Alberto Lozano ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Habitat Specialization ◽  
Evolutionary Significance ◽  
Chromosomal Variation ◽  
Gulf Of Cadiz ◽  
Habitat Specialist ◽  
Isolated Populations ◽  
Distributional Range ◽  
Gulf Of Cádiz ◽  
Chromosomal Differentiation

The genus Crocidura represents a remarkable model for the study of chromosome evolution. This is the case of the lesser white-toothed shrew (Crocidura suaveolens), a representative of the Palearctic group. Although continuously distributed from Siberia to Central Europe, C. suaveolens is a rare, habitat-specialist species in the southwesternmost limit of its distributional range, in the Gulf of Cádiz (Iberian Peninsula). In this area, C. suaveolens is restricted to genetically isolated populations associated to the tidal marches of five rivers (Guadiana, Piedras, Odiel, Tinto and Guadalquivir). This particular distributional range provides a unique opportunity to investigate whether genetic differentiation and habitat specialization was accompanied by chromosomal variation. In this context, the main objective of this study was to determinate the chromosomal characteristics of the habitat-specialist C. suaveolens in Southwestern Iberia, as a way to understand the evolutionary history of this species in the Iberian Peninsula. A total of 41 individuals from six different populations across the Gulf of Cádiz were collected and cytogenetically characterized. We detected four different karyotypes, with diploid numbers (2n) ranging from 2n = 40 to 2n = 43. Two of them (2n = 41 and 2n = 43) were characterized by the presence of B-chromosomes. The analysis of karyotype distribution across lineages and populations revealed an association between mtDNA population divergence and chromosomal differentiation. C. suaveolens populations in the Gulf of Cádiz provide a rare example of true karyotypic polymorphism potentially associated to genetic isolation and habitat specialization in which to investigate the evolutionary significance of chromosomal variation in mammals and their contribution to phenotypic and ecological divergence.

Chromosomal Differentiation Among Ecotypes of Phalaris aquatica L.

1980 ◽  
Vol 28 (6) ◽  
pp. 645 ◽  
Author(s):  
E Putievsky ◽  
RN Oram ◽  
K Malafant
Keyword(s):  
Pollen Grains ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Geographic Origins ◽  
Meiotic Irregularities ◽  
Structural Differences ◽  
Two Generations ◽  
Chromosomal Differentiation ◽  
Mother Cells ◽  
F2 Progeny

Seventy-two hybrids of P. aquatica were made among 13 diverse Mediterranean ecotypes and cv. Australian, and five indicators of hybrid abnormality were measured in the first two generations. The proportions of stainable, apparently normal pollen grains formed by F, hybrids varied between 5 and 98% and their spikelet fertility ranged from 19 to 77%. Of the 43 hybrids that were derived from pairs of self-incompatible parents, 13 were highly self-compatible. Crosses between lines from different groups of parents produced F2 progeny containing up to 17% of lethal seedlings and up to 39% of male sterile plants. In the cross between cv. Australian and the Moroccan ecotype, CPI 19331: the frequency ofzebra-striped lethal seedlings was as high as 33% in F2 progenies, but only 0 or 1% in back-crosses to either parent. Hence the zebra-striped phenotype was not caused by a mutation existing in the parents but rather by deletions or duplications generated during meiosis in the F1 hybrids. Many meiotic irregularities were observed in the pollen mother cells of the F1 and F2 hybrids between cv. Australian and CPI 19331. These included small loops, acentric fragments, univalents and multivalents at diakinesis, and bridges at anaphase I, indicating that the genomes of these two lines differed by several inversions and interchanges. These structural differences would lead to a range of duplications and deficiencies in the gametes. and hence could account for each of the five kinds of hybrid abnormality observed in the F1 and F2 generations. One aneuploid F2 plant with 25 chromosomes was found. A dihaploid plant in cv. Australian had an average of 4.3 bivalents per pollen mother cell, whereas virtually all chromosomes in the tetraploid parental lines paired as bivalents. Thus, P. aquatica is a segmental allotetraploid with a system which prevents homoeologous pairing in tetraploids but not in dihaploids. The partial barriers to hybridization between P. aquatica lines are not closely related to their geographic origins or varietal classifications. These barriers may hinder but have not prevented the recombination of parental traits during the development of improved cultivars.

Chromosomal Differentiation among the Annual Helianthus Species

1986 ◽  
Vol 11 (2) ◽  
pp. 354 ◽  
Author(s):  
John M. Chandler ◽  
Chao-Chien Jan ◽  
Benjamin H. Beard
Keyword(s):  
Chromosomal Differentiation ◽  
Helianthus Species

scholarly journals Chromosomal polymorphism in 12 populations of Mikania micrantha (Compositae)

1999 ◽  
Vol 22 (3) ◽  
pp. 433-444 ◽  
Author(s):  
Eliane M.D. Maffei ◽  
M.A. Marin-Morales ◽  
P.M. Ruas ◽  
C.F. Ruas ◽  
N.I. Matzenbacher
Keyword(s):  
Chromosomal Polymorphism ◽  
The United States ◽  
B Chromosomes ◽  
Mitotic Chromosomes ◽  
Mikania Micrantha ◽  
Perennial Weed ◽  
C Banding ◽  
Size Number ◽  
Chromosomal Differentiation ◽  
First Time

Mikania micrantha is a climbing perennial weed of the family Asteraceae, with a vast distribution from South America to south of the United States. This species is widely distributed throughout Brazil, where it shows little morphological variation. Mitotic chromosomes of 12 populations of M. micrantha derived from several Brazilian sites were studied using Feulgen staining and C-banding. The populations included eight diploid (2n = 36 and 42) and four tetraploid (2n = 72) cytotypes. Chromosome numbers of 2n = 36 and 2n = 42 are reported for the first time for M. micrantha. These populations had a secondary constriction in the middle of the larger arm of chromosome pair 1, following the same pattern described for all Mikania species analyzed so far. Numerical and structural variation of the chromosomes was quite common among the karyotypes and nearly all cytotypes differed from each other in some aspect. Most of the chromosomal differentiation may be attributed to inversions and addition or deletion of DNA fragments. C-banding, applied to three of the 12 populations, also revealed polymorphism in the distribution of heterochromatin. Additionally, one to 14 supernumerary or B-chromosomes were observed. The Bs were detected in six of the 12 populations and varied in size, number, and structure among karyotypes and also among cells of the same root meristem. The B chromosomes were also heterochromatic, showing a C-banding pattern similar to the A chromosomes, and suggesting that they may be derived from the chromosomes of the A complement.

CHROMOSOMAL DIFFERENTIATION OF ANOPHELES FUNESTUS FROM LUANDA AND HUAMBO PROVINCES, WESTERN AND CENTRAL ANGOLA

2005 ◽  
Vol 73 (6) ◽  
pp. 1071-1076 ◽  
Author(s):  
DANIELA BOCCOLINI ◽  
IBRAHIMA DIA ◽  
CARLO COSTANTINI ◽  
FILOMENO FORTES ◽  
GIAN CARLO CARRARA ◽  
...  
Keyword(s):  
Anopheles Funestus ◽  
Chromosomal Differentiation

scholarly journals GENIC AND CHROMOSOMAL DIFFERENTIATION IN POCKET GOPHERS OF THEGEOMYS BURSARIUSGROUP

Evolution ◽  
1974 ◽  
Vol 28 (4) ◽  
pp. 557-564 ◽  
Author(s):  
Robert K. Selander ◽  
Donald W. Kaufman ◽  
Robert J. Baker ◽  
Stephen L. Williams
Keyword(s):  
Pocket Gophers ◽  
Chromosomal Differentiation
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