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Homoeologous relationships of rice, wheat and maize chromosomes 总被引:34,自引:0,他引:34
S. Ahn J. A. Anderson M. E. Sorrells S. D. Tanksley 《Molecular & general genetics : MGG》1993,241(5-6):483-490
A set of cDNA clones, which had previously been mapped onto wheat chromosomes, was genetically mapped onto the chromosomes of rice. The resulting comparative maps make it possible to estimate the degree of linkage conservation between these two species. A number of chromosomal rearrangements, some of which must have involved interchromosomal translocations, differentiate the rice and wheat genomes. However, synteny of a large proportion of the loci appears to be conserved between the two species. The results of this study, combined with those from a recently published comparative map of the rice and maize genomes, suggest that rice, wheat and maize share extensive homoeologies in a number of regions in their genomes. Some chromosomes (e.g. chromosome 4 in rice, chromosomes 2 and 2S in wheat and maize, respectively) may have escaped major rearrangement since the divergence of these species from their last common ancestor. Comparative maps for rice, wheat and maize should make it possible to begin uniting the genetics of these species and allow for transfer of mapping information (including centromere positions) and molecular marker resources (e.g. RFLP probes) between species. In addition, such maps should shed light on the nature of chromosome evolution that accompanied the radiation of grasses in the early stages of plant diversification. 相似文献
2.
Motomi Ito Tetsukazu Yahara Robert M King Kuniaki Watanabe Sanae Oshita Jun Yokoyama Daniel J Crawford 《Journal of plant research》2000,113(1):91-96
Neomirandea (x=17 and 25), Ageratina (x=17) and Sclerolepis (x=15) with the higher chromosome base numbers, and the other includes Mikania (x=17) and the remaining genera with lower chromosome base numbers (x=10–11). However, the monophyly of the former clade is supported with a low bootstrap value. In the latter clade, Mikania (x=17) diverged first, then Stevia (x=11), and finally eight genera with x=10 diverged in succession. This result supports the hypothesis that the genera in the tribe Eupatorieae with x =10 evolved from an ancestor with a higher base number, and the tribe is of polyploid origin.
Received 13 September 1999/ Accepted in revised form 20 January 2000 相似文献
3.
E. Martel V. Poncet F. Lamy S. Siljak-Yakovlev B. Lejeune A. Sarr 《Plant Systematics and Evolution》2004,249(3-4):139-149
4.
Elke Bellefroid S. Khadijah Rambe Olivier Leroux Ronald L. L. Viane 《Annals of botany》2010,106(1):157-171
Background and Aims
‘Loxoscaphoid’ Asplenium species are morphologically a remarkably distinct group of Aspleniaceae. Except for two preliminary chromosome counts of Asplenium theciferum, the cytology of this group of species has, however, been largely unstudied.Methods
Chromosome counts were obtained by acetocarmine squash preparations of one mitotic cell and several meiotic cells. Relative DNA content of gametophytic and sporophytic cells was determined by flow cytometry. The phylogenetic placement of A. loxoscaphoides, A. rutifolium s.l. and A. theciferum s.l. was investigated through an analysis of rbcL sequences.Key Results
The dysploid base number is reported to be x = 35 in Asplenium centrafricanum, A. loxoscaphoides, A. sertularioides and A. theciferum. Analysis of rbcL sequences confirms that ‘loxoscaphoids’ nest robustly within Asplenium. Several high ploidy levels exceeding the tetraploid level were found in A. theciferum s.l. and A. rutifolium s.l. All taxa proved to be sexual.Conclusions
Four base numbers are known at present for Aspleniaceae: x = 39, 38, 36 and 35. The dysploid base number x = 35 found in the ‘loxoscaphoid’ Asplenium spp. sheds a novel light on the cytoevolution of the whole family. We postulate a recurrent descending dysploid evolution within Aspleniaceae, leading to speciation at the (sub)generic and species/group level. 相似文献5.
Ming-Cheng Luo Frank M. You Pingchuan Li Ji-Rui Wang Tingting Zhu Abhaya M. Dandekar Charles A. Leslie Mallikarjuna Aradhya Patrick E. McGuire Jan Dvorak 《BMC genomics》2015,16(1)
Background
Mutations often accompany DNA replication. Since there may be fewer cell cycles per year in the germlines of long-lived than short-lived angiosperms, the genomes of long-lived angiosperms may be diverging more slowly than those of short-lived angiosperms. Here we test this hypothesis.Results
We first constructed a genetic map for walnut, a woody perennial. All linkage groups were short, and recombination rates were greatly reduced in the centromeric regions. We then used the genetic map to construct a walnut bacterial artificial chromosome (BAC) clone-based physical map, which contained 15,203 exonic BAC-end sequences, and quantified with it synteny between the walnut genome and genomes of three long-lived woody perennials, Vitis vinifera, Populus trichocarpa, and Malus domestica, and three short-lived herbs, Cucumis sativus, Medicago truncatula, and Fragaria vesca. Each measure of synteny we used showed that the genomes of woody perennials were less diverged from the walnut genome than those of herbs. We also estimated the nucleotide substitution rate at silent codon positions in the walnut lineage. It was one-fifth and one-sixth of published nucleotide substitution rates in the Medicago and Arabidopsis lineages, respectively. We uncovered a whole-genome duplication in the walnut lineage, dated it to the neighborhood of the Cretaceous-Tertiary boundary, and allocated the 16 walnut chromosomes into eight homoeologous pairs. We pointed out that during polyploidy-dysploidy cycles, the dominant tendency is to reduce the chromosome number.Conclusion
Slow rates of nucleotide substitution are accompanied by slow rates of synteny erosion during genome divergence in woody perennials.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1906-5) contains supplementary material, which is available to authorized users. 相似文献6.
Kuniaki Watanabe Tetsukazu Yahara Tetsuo Denda Keiko Kosuge 《Journal of plant research》1999,112(2):145-161
Brachyscome and 8 taxa of its allied genera, Australian Astereae. Statistical tests regarding correlations between changes in chromosome
number, total chromosome length, mean chromosome length, karyotypic asymmetry and chromosome length heterogeneity and changes
in habit were performed based on the matK molecular phylogenetic tree. The reductions in chromosome number and total chromosome length, and the increases in mean chromosome
length, chromosome length heterogeneity and karyotypic asymmetry were found to be correlated with the change in habit from
perennial to annual. A reduction in total chromosome length is favored to shorten the mitotic cell cycle and to produce smaller
cells conducive to more rapid development of smaller annuals under the time-limited environment. Stepwise dysploidal reductions
in chromosome number were achieved through the translocation of large chromosome segments onto other chromosomes, followed
by the loss of a centromere, resulting in one fewer linkage group and one fewer haploid chromosome. The correlations between
the dysploidal reduction in chromosome number and the increases in mean chromosome length, length heterogeneity and asymmetry
in karyotype can be attributed to this mode of chromosomal change. These changes occurred independently in several different
lineages in Brachyscome.
Received 27 May 1998/ Accepted in revised form 18 January 1999 相似文献
7.
Chromosome numbers are determined from 37 populations attributed to 22 taxa of JapaneseArisaema. Of them, chromosome numbers ofA. limbatum var.conspicuum (2n=26),A. minus (2n=26),A. nambae (2n=28) andA. seppikoense (2n=26) are determined for the first time. New chromosome numbers, 2n=26, are reported forA. aequinoctiale, A. limbatum, A. stenophyllum, A. undulatifolium andA. yoshinagae. Three modes of basic chromosome numbers,x=14,x=13 andx=12, occur in JapaneseArisaema. Precise karyotypic comparisons of 20 taxa reveal that taxa withx=14 andx=13 share 26 major chromosome arms and have an obvious chromosomal relationship. One of two submeta-centric chromosomes inx=13 corresponds to two telo-centric chromosomes inx=14. InA. ternatipartitum with 2n=6x=72, ten out of 12 basic chromosomes are the most similar in size and arm ratio with larger ten chromosomes ofA. ringens among JapaneseArisaema examined. A basic chromosome number ofx=14 is the commonest in the genusArisaema and the remaining basic chromosome numbers,x=13 andx=12, seem to be derived through dysploidal reduction by translocating large segments of major arm of telo-centric chromosome
onto other minor arm of telo-centric followed by loss of the remainings including a centromere, and by loss of two telo-centrics
fromx=14, respectively. Some systematic problems of JapaneseArisaema are discussed based on new cytological data.Arisaema hatizyoense, A. minus andA. nambae are accepted as independent species. 相似文献
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Cordula Blch Hanna Weiss-Schneeweiss Gerald M. Schneeweiss Michael H.J. Barfuss Carolin A. Rebernig Jos Luis Villaseor Tod F. Stuessy 《Molecular phylogenetics and evolution》2009,53(1):220-233
Chromosome evolution (including polyploidy, dysploidy, and structural changes) as well as hybridization and introgression are recognized as important aspects in plant speciation. A suitable group for investigating the evolutionary role of chromosome number changes and reticulation is the medium-sized genus Melampodium (Millerieae, Asteraceae), which contains several chromosome base numbers (x = 9, 10, 11, 12, 14) and a number of polyploid species, including putative allopolyploids. A molecular phylogenetic analysis employing both nuclear (ITS) and plastid (matK) DNA sequences, and including all species of the genus, suggests that chromosome base numbers are predictive of evolutionary lineages within Melampodium. Dysploidy, therefore, has clearly been important during evolution of the group. Reticulate evolution is evident with allopolyploids, which prevail over autopolyploids and several of which are confirmed here for the first time, and also (but less often) on the diploid level. Within sect. Melampodium, the complex pattern of bifurcating phylogenetic structure among diploid taxa overlain by reticulate relationships from allopolyploids has non-trivial implications for intrasectional classification. 相似文献
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