Karyotyping of three Pinaceae species via fluorescent in situ hybridization and computer-aided chromosome analysis

The positions of 18/25S rRNA genes, 5S RNA genes and of Arabidopsis-type telomeric repeats were localized by fluorescent in situ hybridization (FISH) on the chromosomes of three coniferous species; Picea abies, Larix decidua and Pinus sylvestris, each with 2n=24 chromosomes. Computer-aided chromosome analysis was performed on the basis of the chromosome length, the arm length ratio and the position of the hybridization signals. This enabled the chromosomes of the Norway spruce, 4 chromosomes of the European larch and 3 of the karyotype of the Scots pine to be individually distinguished. With respect to the chromosomal positions of rDNA and 5S rDNA loci, chromosome pair I of P. sylvestris is suggested to be homoeologous to pair II of P. abies, while another chromosome pair of P. sylvestris might be homoeologous to chromosome pair III of L. decidua.