[Intraspecific divergence in wheats of the Emmer group using in situ hybridization with the Spelt1 family of tandem repeats].

Fluorescence in situ hybridization (FISH) was used to study the distribution of Spelt1 repetitive DNA sequences on chromosomes of 37 accessions representing eight polyploidy wheat species of the Emmer evolutionary lineage: Triticum dicoccoides Körn, T. dicoccum (Schrank) Schuebel, T. durum Desf., T. polonicum L., T. carthlicum Nevski, T. aethiopicum Jabbz., T. aestivum L., and T. spelta L. Substantial polymorphism in the number, distribution, and the sizes of the Spelt1 loci was revealed. On the chromosomes of the accessions examined, Spelt1 tandem repeats were found in seven different positions (per haploid chromosome set). These were "potential hybridization sites", including the subtelomeric regions of either short or long arms of chromosomes 2A and 6B, the short arm of chromosome 1B, and the long arms of chromosomes 2B and 3B. However, in individual genotypes, only from one to three Spelt1 loci were revealed. Furthermore, no hybridization with Spelt1 probe was detected on chromosomes from 12 accessions. Thus, the total number of Spelt1 sites in karyotypes varied from zero to three, with the average number of 1.16. This was substantially lower than in the species of the Timopheevi section and diploid Aegilops speltoides Tausch, a putative donor of the B genome. The decrease of the content of Spelt1 sequences in the genomes of the Emmer group wheats in comparison with the species of the Timopheevii group and diploid Ae. speltoides was assumed to result from the repetitive sequences reorganization during polyploidization and the repeat elimination during wheat evolution.

[Intraspecific divergence in wheats of the Timopheevi group as revealed by in situ hybridization with tandem repeats of the Spelt1 and Spelt52 families].

Fluorescent in situ hybridization (FISH) was used to study the distribution of the Spelt1 and Spelt52 repetitive DNA sequences on chromosomes of ten accessions representing three polyploid wheat species of the Timopheevi group: Triticum araraticum (7), T. timopheevii (2), and T. kiharae (1). Sequences of both families were found mostly in the subtelomeric chromosome regions of the G genome. The total number of Spelt1 sites varied from 8 to 14 in the karyotypes of the species under study; their number, location, and size differed among the seven T. araraticum accessions and were the same in the two T. timopheevii accessions and T. kiharae, an amphidiploid T. timopheevii-Aegilops tauschii hybrid. The Spelt52 tandem repeat was detected in the subtelomeric regions of chromosomes 1-4; its sites did not coincide with the Spelt1 sites. The chromosome distribution and signal intensity of the Spelt52 repeats varied in T. araraticum and were the same in T. timopheevii and T. kiharae. The chromosome distributions of the Spelt1 and Spelt52 repeats were compared for the polyploid wheats of the Timopheevi group and diploid Ae. speltoides, a putative donor of the G genome. The comparison revealed a decrease in hybridization level: both the number of sites per genome and the size of sites were lower. The decrease was assumed to result from repeat elimination during polyploidization and subsequent evolution of wheat and from the founder effect, since the origin of Timopheevi wheats might involve the genotype of Ae. speltoides, which is highly polymorphic for the distribution of Spelt1 and Spelt52 sequences and is similar in the chromosome location of the repeats to modern wheat.

[History of modern chromosomal analysis. Differential staining of plant chromosomes]. / Istoriia sovremennogo khromosomnogo analiza. Differential'noe okrashivanie khromosom rastenii.

Differential staining methods found extensive use in karyotype studies of many plant and animal species and provide for reliable identification of all chromosomes of the organism. Below we describe the most widespread methods and history of their advent. In addition, we discuss specific structure of the chromosomes and possible mechanisms responsible for differential segmentation.

[The history of modern chromosome analysis. The founding contribution of the works of Caspersson]. / Istoriia sovremennogo khromosomnogo analiza. Osnovopolagaiushchii vklad rabot Kaspersona.

Chromosome analysis based on the studies of individual chromosomes is widely used in medical genetics, selection, and molecular biology. The "Human Genome" program based on studies of individual chromosomes is aimed at the complete sequencing of the human genome. The nature of the differential stainability of the chromosomes of different organisms (Rodionov, 1999) and the identity or difference of individual types of their banding are discussed.