Genomic relationships between Dasypyrum villosum (L.) Candargy and D. hordeaceum (Cosson et Durieu) Candargy

Genome ◽  
1996 ◽  
Vol 39 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. Blanco ◽  
R. Simeone ◽  
P. Resta ◽  
C. De Pace ◽  
V. Delre ◽  
...  

The origin and genomic constitution of the tetraploid perennial species Dasypyrum hordeaceum (2n = 4x = 28) and its phylogenetic relationships with the annual diploid Dasypyrum villosum (2n = 2x = 14) have been investigated by comparing the two genomes using different methods. There is no apparent homology between the conventional or Giemsa C-banded karyotypes of the two Dasypyrum species, nor can the karyotype of D. hordeaceum be split up into two similar sets. Polymorphism within several chromosome pairs was observed in both karyotypes. Cytophotometric determinations of the Feulgen–DNA absorptions showed that the genome size of D. hordeaceum was twice as large as that of D. villosum. Both the cross D. villosum × D. hordeaceum (crossability rate 12.1%) and the reciprocal cross (crossability rate 50.7%) produced plump seeds. Only those from the former cross germinated, producing sterile plants with a phenotype that was intermediate between those of the parents. In these hybrids (2n = 21), an average of 13.77 chromosomes per cell paired at meiotic metaphase I. Trivalents were only rarely observed. Through dot-blot hybridizations, a highly repeated DNA sequence of D. villosum was found not to be represented in the genome of D. hordeaceum. By contrast, very similar restriction patterns were observed when a low-repeated DNA sequence or different single-copy sequences of D. villosum or two sequences in the plastidial DNA of rice were hybridized to Southern blots of the genomic DNAs of the two Dasypyrum species digested with different restriction endonucleases. By analyzing glutamic-oxaloacetic-transaminase, superoxide dismutase, alcohol dehydrogenase, and esterase isozyme systems, it was shown that both Dasypyrum species shared the same phenotypes, which differed from those found in hexaploid wheat. In situ hybridizations using DNA sequences encoding gliadins showed that these genes were located close to the centromere of three pairs of D. villosum chromosomes and that they had the same locations in six pairs of D. hordeaceum chromosomes. We conclude that the autoploid origin of D. hordeaceum from D. villosum, which cannot be defended on the basis of chromosomal traits, is suggested by the other findings obtained by comparing the two genomes. Key words : Dasypyrum hordeaceum, Dasypyrum villosum, phylogenetic relationships.

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 944-953 ◽  
Author(s):  
Xinping Zhao ◽  
Gary Kochert

We have characterized a repeated DNA sequence (RTL 122) from rice (Oryza sauva L.) with respect to its organization in the rice genome and its distribution among rice and other plants. The results indicate that the RTL 122 sequence is interspersed in the rice genome and limited to the genus Oryza. It is highly polymorphic and can be used to fingerprint rice varieties. A structure was observed in which several repeated sequences were clustered in DNA regions of 15–20 kb. We characterized three bacteriophage lambda clones that contained the RTL 122 sequence. Southern analysis using probes derived from restriction fragments of the three lambda clones indicated that all fragments except one are interspersed repeated sequences and belong to different repeated sequence families. Subsequent slot blot hybridization showed that most of them are only present within the genus Oryza. Some of the Oryza-specific, physically linked sequences show the same phylogenetic distribution, which suggests that these sequences might have evolved in a coordinate fashion. On the other hand, some of the repeated sequences have a different distribution even though they are physically adjacent in the genome. We speculate that such blocks of interspersed repeated sequences may serve as hotspots for rapid changes in the rice genome.Key words: rice, Oryza, repeated sequences, DNA fingerprinting, coordinated evolution.


1986 ◽  
Vol 204 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Jose M. Martinez-Zapater ◽  
Mark A. Estelle ◽  
Chris R. Somerville

2009 ◽  
Vol 124 (1) ◽  
pp. 27-36 ◽  
Author(s):  
M.J. Acosta ◽  
J.A. Marchal ◽  
G.P. Mitsainas ◽  
M.T. Rovatsos ◽  
C.H. Fernández-Espartero ◽  
...  

1985 ◽  
Vol 13 (6) ◽  
pp. 1965-1975 ◽  
Author(s):  
Ramareddy V. Guntaka ◽  
Siddarame Gowda ◽  
Arepalli S. Rao ◽  
Theodore J. Green

Genome ◽  
1992 ◽  
Vol 35 (6) ◽  
pp. 1037-1044 ◽  
Author(s):  
Cort S. Madsen ◽  
Kevin P. McHugh ◽  
Siwo R. de Kloet

We have investigated the evolution of a 190 base pair tandemly repeated DNA sequence (RBMII) in 27 different species of waterfowl. In this paper we show that the RBMII sequence is present in many species belonging to 7 of the 11 Anatid tribes. Inter- and intra-tribal differences in repeat presence indicate that, although the RBMII sequence has been maintained among widely divergent species, it is rapidly evolving. Restriction enzyme analyses suggest very different hierarchical repeat organizations among different species. DNA sequence comparisons of 32 cloned monomer units from five different species revealed what appears to be a nonrandom distribution of sequence divergence, as well as large differences (up to 25-fold) in intraspecific sequence variation between relatively closely related species.Key words: repeated DNA, Anatidae, sequence variation.


1992 ◽  
Vol 18 (3) ◽  
pp. 603-605 ◽  
Author(s):  
Marta Dobrzańska ◽  
Blanka Szurmak

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