Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

Sessione: Varie

Presentazione preferita: Poster

FISH LANDMARKS FOR NORWAY SPRUCE CHROMOSOMES

JURMAN I., VISCHI M., Vischi M., Jurman I. ZUCCOLO A., OLIVIERI A.M.

Dipartimento di Produzione Vegetale e Tecnologie Agrarie, Universiaà di Udine, Via delle Scienze 208, 33100 Udine

massimo.vischi@dpvta.uniud.it

Dipartimento di Produzione Vegetale e Tecnologie Agrarie

Università di Udine

Via delle Scienze 208, 33100 Udine

e-mail: massimo.vischi@dpvta.uniud.it

Key words: Norway spruce, FISH, repetitive DNA, retrotransposon.

Norway spruce (Picea abies L.K.), as well asall other conifers, has a very large genome (C = 3015 x 10⁹ bp ).

Despite their large size,s of the genome the lack of morphological variability in chromosomes impedimpedes progress to uniquely and unambiguously identify and orient of the 12 pairs of long (>10 mm), metacentric chromosomes via visual inspection. Fluorescence in situ hybridization (FISH) is a technique that has been used widely to physically map DNA sequences to chromosomes.

The Norway spruce huge genome is largely composed by repetitive sequences, 119 highly repetitive clones were isolated and sequenced. Homology searches using BlastN, BlastX and FastA allowed us to classify them into families and groups of ripetitive DNA (tandem repeat and LTR-retrotransposon)

DNA sequences have been sought which would mark the chromosomes unambiguously. The Norway spruce genome is largely composed by repetitive sequences. 119 highly repetitive clones were isolated and sequenced. Homology searches using BlastN, BlastX and FastA allowed us to classify them into families and groups of repetitive DNA (tandem repeats and LTR-retrotransposon) Probe Some of these sequences have been tested as probes inby FISH experiments to determine their usefulness as physical chromosomal markers.

In situ hybridization was carried out to root-tip metaphase chromosome with 15 probes reapresentative of all the major families identified so fary. Eight of these probes have given satisfactory results in single and multiple label FISH experiments. 2Two tandemly repeated familiesy (PATR140, PATR190), 2 gypsy-like familiesy of retrotransposons (Aifor15, PAB5B8) and 1 copia-like retrotransposon (PAA1B5) co-localized on 3 chromosome pairs at the centromeric level. PAA1B5 is present at one more centromeric site at low stringency (65%). The Aifor15 sequence is distributed in the whole chromosome complement particularly in the subtelomeric regions. Alisei , an abundant gypsy –like retrotransposon, is interspersed: the probe hybridizes toin the whole chromosome complement withat different levels of intensity (stronger in the subtelomeric regions). Other two probes (PAF1, PAD6) hybridizes in 6 subtelomeric sites and co-localizes with the 28S rDNA.

Among theise probes, PATR140, PAD6 and PAF1 results useful for the identification of the chromosomes and for the Norway spruce karyotyping.