Dynamics of tandem repetitive Afa-family sequences in Triticeae, wheat-related species.
The Afa-family sequences in wheat-related species, Triticeae, are tandem repetitive sequences of 340 bp. All the analyzed Triticeae species carried the sequences in their genomes, though the copy numbers varied about 100-fold among the species. The nucleotide fragments amplified by PCR were cloned and sequenced, and their behavior in the evolution of Triticeae was analyzed by the neighbor-joining (NJ) method. The sequences in genomes with many copies of this family clustered at independent branches of the phylogenic tree, whereas the sequences in genomes with a few copies did not. This may suggest that Afa-family sequences had amplified several times in the evolution of Triticeae, each using a limited number of different master copies. In addition, the sequences of the A and B genomes of hexaploid common wheat indicated that the Afa-family sequences had not evolved in a concerted manner between the genomes. Furthermore, the sequences of each chromosome of the D genome of this species indicated that the sequences had amplified on all over the D-genome chromosomes in a short period.
Nagaki
K
K
Kihara Institute Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama 244, Japan. nagaki@yokohama-cu.ac.jp
Tsujimoto
H
H
Sasakuma
T
T
D001483:Base Sequence; D003001:Cloning, Molecular; D002523:Edible Grain / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D005784:Gene Amplification; D018628:Gene Dosage; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D011003:Ploidies; D006109:Poaceae / Q000145:classification / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014908:Triticum / Q000145:classification / Q000235:genetics*