Tandem repeats of Allium fistulosum associated with major chromosomal landmarks.

Tandem repeats are often associated with important chromosomal landmarks, such as centromeres, telomeres, subtelomeric, and other heterochromatic regions, and can be good candidates for molecular cytogenetic markers. Tandem repeats present in many plant species demonstrate dramatic differences in unit length, proportion in the genome, and chromosomal organization. Members of genus Allium with their large genomes represent a challenging task for current genetics.

Towards a FISH-based karyotype of L. (Rosaceae).

The genus Linnaeus, 1753 has important economic value in ornamental sector and many breeding activities are going on supported by molecular studies. However, the cytogenetic studies of rose species are scarce and mainly focused on chromosome counting and chromosome morphology-based karyotyping. Due to the small size of the chromosomes and a high frequency of polyploidy in the genus, karyotyping is very challenging for rose species and requires FISH-based cytogenetic markers to be applied.

Variation in Copy Number of Ty3/Gypsy Centromeric Retrotransposons in the Genomes of Thinopyrum intermedium and Its Diploid Progenitors.

Speciation and allopolyploidization in cereals may be accompanied by dramatic changes in abundance of centromeric repeated transposable elements. Here we demonstrate that the reverse transcriptase part of Ty3/gypsy centromeric retrotransposon (RT-CR) is highly conservative in the segmental hexaploid Thinopyrum intermedium (JrJvsSt) and its possible diploid progenitors Th. bessarabicum (Jb), Pseudoroegneria spicata (St) and Dasypyrum villosum (V) but the abundance of the repeats varied to a large extent.

High resolution physical mapping of single gene fragments on pachytene chromosome 4 and 7 of Rosa.

Background: Rosaceae is a family containing many economically important fruit and ornamental species. Although fluorescence in situ hybridization (FISH)-based physical mapping of plant genomes is a valuable tool for map-based cloning, comparative genomics and evolutionary studies, no studies using high resolution physical mapping have been performed in this family. Previously we proved that physical mapping of single-copy genes as small as 1.

Alien genes introgression and development of alien monosomic addition lines from a threatened species, Allium roylei Stearn, to Allium cepa L.

To produce alien monosomic addition lines (AMALs) of Allium cepa (genomes CC, 2n = 2x = 16) carrying extrachromosomes from Allium roylei (RR, 2n = 2x = 16), reciprocal backcrossing of allotriploids (2n = 24, CCR) with diploids (2n = 16, CC) and selfing of a single allotriploid were carried out. The chromosome numbers in the BC(2)F(1) and BC(1)F(2) progenies ranged from 16 to 32. Forty-eight plants were recorded to possess 2n = 17 among a total of 169 plants in observation.