A cytogenetic analysis of the chromosomes in two related species of the genus Muscari (Liliaceae)

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 729-732 ◽  
Author(s):  
C. Ruiz Rejón ◽  
R. Lozano ◽  
M. Ruiz Rejón
Keyword(s):  
Related Species ◽  
Cytogenetic Analysis ◽  
Chromosome Pair ◽  
Chromosomal Evolution ◽  
Closely Related Species ◽  
Positive Band ◽  
Nucleolus Organizing Region ◽  
Cytogenetic Analyses

Muscari comosum L. and Muscari matritensis Ruiz Rejón et al. are two closely related species of the subgenus Leopoldia, belonging to the genus Muscari (Liliaceae). Cytogenetic analyses have been made to analyse the differences between these species. Major differences are that M. comosum has four or five dark intercalary 4,6-diamidino-2-phenylindole (DAPI) positive C-bands in the first chromosome pair, whereas M. matritensis has only three thin bands. Muscari comosum has a large chromomycin A3 positive C-band in the fifth, nucleolus organizing region (NOR) bearing chromosome pair, whereas M. matritensis has the CMA3-positive band and the NOR in the short arm of the second pair. The possible role played by occurrences of translocations and amplifications in the chromosomal evolution of these species is discussed.Key words: Muscari, Liliaceae, karyotypes, evolution.

Metaphase karyotypes of fruit flies of Thailand. I. Five sibling species of the Bactrocera dorsalis complex

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
V. Baimai ◽  
W. Trinachartvanit ◽  
P. J. Grote ◽  
U. Kijchalao ◽  
S. Tigvattananont ◽  
...  
Keyword(s):  
X Chromosome ◽  
Related Species ◽  
Constitutive Heterochromatin ◽  
Chromosomal Evolution ◽  
Pericentric Heterochromatin ◽  
Bactrocera Dorsalis ◽  
Centromeric Heterochromatin ◽  
Chromosomal Variation ◽  
Closely Related Species ◽  
Group 3

Natural populations of fruit flies of the Bactrocera dorsalis complex exhibit chromosomal variation based on differences in the amount and distribution of constitutive heterochromatin in the centromeric regions of the autosomes and the sex chromosomes. The chromosomal variation, coupled with differences in external morphology and host plant specific preferences, strongly suggest the existence of 5 closely related species within the B. dorsalis complex that have provisionally been designated B. dorsalis species B, C, D, and E in contrast with B. dorsalis s.s. (species A). Analysis of heterochromatin in autosomes and sex chromosomes has revealed 4 distinct groups of mitotic karyotypes. Bactrocera dorsalis is the only representative of Group I, which is characterized by the typical metacentric X chromosome and major blocks of centromeric heterochromatin in autosomes 5 and 6. Group 2 consists of species B and C, which show prominent landmarks of pericentric heterochromatin in all autosomes and in the X chromosome. Group 3 comprises species D, which is characterized by conspicuous blocks of pericentric heterochromatin in all autosomes but the long arm of the subtelocentric X chromosome is euchromatic and lacks a major portion of centromeric heterochromatin. Species E belongs to Group 4, which differs from Group 3 in having major blocks of heterochromatin at the distal portion of the X chromosome in addition to the prominent landmarks of pericentric heterochromatin in all autosomes. Chromosomal evolution among closely related species within the B. dorsalis complex clearly involves the presence or absence of constitutive heterochromatin in the centromeric regions of autosomes as well as in the X chromosome.Key words: Bactrocera dorsalis complex, metaphase karyotype, heterochromatin, chromosomal evolution.

Differential occurrence of chromosome inversion polymorphisms among Muller's elements in three species of the tripunctata group of Drosophila, including a species with fast chromosomal evolution

Genome ◽  
2013 ◽  
Vol 56 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Mitsue T. Brianti ◽  
Galina Ananina ◽  
Louis B. Klaczko
Keyword(s):  
Pericentric Inversion ◽  
Chromosome Pair ◽  
Genetic Architecture ◽  
Polytene Chromosomes ◽  
Chromosomal Evolution ◽  
Chromosome Inversion ◽  
Closely Related Species ◽  
Chromosome Inversions ◽  
Chromosome Maps ◽  
Chromosome Fusions

Detailed chromosome maps with reliable homologies among chromosomes of different species are the first step to study the evolution of the genetic architecture in any set of species. Here, we present detailed photo maps of the polytene chromosomes of three closely related species of the tripunctata group (subgenus Drosophila): Drosophila mediopunctata, D. roehrae, and D. unipunctata. We identified Muller's elements in each species, using FISH, establishing reliable chromosome homologies among species and D. melanogaster. The simultaneous analysis of chromosome inversions revealed a distribution pattern for the inversion polymorphisms among Muller's elements in the three species. Element E is the most polymorphic, with many inversions in each species. Element C follows; while the least polymorphic elements are B and D. While interesting, it remains to be determined how general this pattern is among species of the tripunctata group. Despite previous studies showing that D. mediopunctata and D. unipunctata are phylogenetically closer to each other than to D. roehrae, D. unipunctata shows rare karyotypic changes. It has two chromosome fusions: an additional heterochromatic chromosome pair and a pericentric inversion in the X chromosome. This especial conformation suggests a fast chromosomal evolution that deserves further study.

A contribution to Centaurea sect. Microlophus (Asteraceae, Cardueae) in Iran

Phytotaxa ◽  
2018 ◽  
Vol 361 (2) ◽  
pp. 151
Author(s):  
MASSOUD RANJBAR ◽  
ALI ASKARI ◽  
SOMEH MOHAMMADI
Keyword(s):  
New Species ◽  
Chromosome Segregation ◽  
Chromosome Numbers ◽  
Related Species ◽  
Conservation Status ◽  
Base Number ◽  
Closely Related Species ◽  
Ploidy Levels ◽  
Sw Iran ◽  
Cytogenetic Analyses

Centaurea masjedsoleymanensis endemic to SW Iran and C. palanganensis endemic to W Iran are described as new species and illustrated. Centaurea masjedsoleymanensis is distinguished from its closely related species, C. pabotii, by having shorter median and upper cauline leaves, a spine of phyllaries up to 4 mm long, incised median cauline leaves, and smaller upper cauline leaves. Centaurea palanganensis is distinguished from C. thracica by having decurrent median cauline leaves, oblong or elliptic basal cauline leaves, phyllaries with a median appendage 10–13 mm long and a spine up to 2 mm long. The IUCN conservation status of both new species is evaluated as Vulnerable (VU). Results from cytogenetic analyses indicated that new taxa are diploid (2n = 2x = 16), which is consistent with the proposed base number of x = 8 for the genus. Meiosis was observed as regular, with bivalent pairing and normal chromosome segregation. Based on the results x = 8 and 9 was determined for C. sect. Microlophus. The relationships between chromosome numbers, geographical distribution and ploidy levels indicate that both aneuploidy and polyploidy have played an important role in the speciation processes in this section.

Microsatellite Marker: Importance and Implications of Cross-genome Analysis for Finger Millet (Eleusine coracana (L.) Gaertn)

2020 ◽  
Vol 9 (3) ◽  
pp. 160-170
Author(s):  
Thumadath P.A. Krishna ◽  
Maharajan Theivanayagam ◽  
Gurusunathan V. Roch ◽  
Veeramuthu Duraipandiyan ◽  
Savarimuthu Ignacimuthu
Keyword(s):  
Molecular Marker ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Genome Analysis ◽  
Related Species ◽  
Finger Millet ◽  
Crop Improvement ◽  
Human Beings ◽  
Closely Related Species ◽  
Genome Amplification

Finger millet is a superior staple food for human beings. Microsatellite or Simple Sequence Repeat (SSR) marker is a powerful tool for genetic mapping, diversity analysis and plant breeding. In finger millet, microsatellites show a higher level of polymorphism than other molecular marker systems. The identification and development of microsatellite markers are extremely expensive and time-consuming. Only less than 50% of SSR markers have been developed from microsatellite sequences for finger millet. Therefore, it is important to transfer SSR markers developed for related species/genus to finger millet. Cross-genome transferability is the easiest and cheapest method to develop SSR markers. Many comparative mapping studies using microsatellite markers clearly revealed the presence of synteny within the genomes of closely related species/ genus. Sufficient homology exists among several crop plant genomes in the sequences flanking the SSR loci. Thus, the SSR markers are beneficial to amplify the target regions in the finger millet genome. Many SSR markers were used for the analysis of cross-genome amplification in various plants such as Setaria italica, Pennisetum glaucum, Oryza sativa, Triticum aestivum, Zea mays and Hordeum vulgare. However, there is very little information available about cross-genome amplification of these markers in finger millet. The only limited report is available for the utilization of cross-genome amplified microsatellite markers in genetic analysis, gene mapping and other applications in finger millet. This review highlights the importance and implication of microsatellite markers such as genomic SSR (gSSR) and Expressed Sequence Tag (EST)-SSR in cross-genome analysis in finger millet. Nowadays, crop improvement has been one of the major priority areas of research in agriculture. The genome assisted breeding and genetic engineering plays a very crucial role in enhancing crop productivity. The rapid advance in molecular marker technology is helpful for crop improvement. Therefore, this review will be very helpful to the researchers for understanding the importance and implication of SSR markers in closely related species.

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