Localization of BAC clones on mitotic chromosomes of Musa acuminata using fluorescence in situ hybridization

Hřibová, E., Doleželová, M., Doležel, J.
BIOLOGIA PLANTARUM 52: 445-452, 2008

Klíčová slova: cytogenetic mapping; chromosome structure; repetitive DNA; ribosomal DNA; subcloning
Abstrakt: A bacterial artificial chromosome (BAC) library of banana (Musa acuminata) was used to select BAC clones that carry low amounts of repetitive DNA sequences and could be suitable as probes for fluorescence in situ hybridization (FISH) on mitotic metaphase chromosomes. Out of eighty randomly selected BAC clones, only one clone gave a single-locus signal on chromosomes of M. acuminata cv. Calcutta 4. The clone localized on a chromosome pair that carries a cluster of 5S rRNA genes. The remaining BAC clones gave dispersed FISH signals throughout the genome and/ or failed to produce any signal. In order to avoid the excessive hybridization of repetitive DNA sequences, we subcloned nineteen BAC clones and selected their 'low-copy' subclones. Out of them, one subclone gave specific signal in secondary constriction on one chromosome pair; three subclones were localized into centromeric and peri-centromeric regions of all chromosomes. Other subclones were either localized throughout the banana genome or their use did not result in visible FISH signals. The nucleotide sequence analysis revealed that subclones, which localized on different regions of all chromosomes, contained short fragments of various repetitive DNA sequences. The chromosome-specific BAC clone identified in this work increases the number of useful cytogenetic markers for Musa.
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Autoři z ÚEB: Jaroslav Doležel, Eva Hřibová