A BAC library for the study of the structure a banana plant chromosomes
2001
Lagoda, Pierre
The banana is a giant herbaceous plant that may grow to between 1.5 and 8 metres in height. The fruit of cultivated banana (cultivars) are the only ones to be eaten. They are seedless, whereas the fruits of wild banana plants contain seeds about 5 mm in diameter. The cultivars are divided into two subgroups: sweet bananas (or dessert bananas) and cooking bananas, among which plantains are the most important. The cultivars, of interspecific origin, are classified according to their ploidy level (number of chromosomes) and the relative contribution of the species #Musa acuminata# (genome A) and #Musa balbisiana# (genome B) to the characteristics of the clone considered. All the wild #acuminata# and #balbisiana# forms are diploid, 2n=2x=22. There are six main genomic groups: AA, AAA, AB, AAB, ABB, ABBB. In addition to the contribution (different proportions) of genomes A and B, there are also translocations, exchanges and inversions in each of the two genomes, although their frequency is unknown. The availability of large fragments of DNA combined with in situ hybridization to chromosomes (FISH, Fluorescent #In Situ# Hybridization) should lead to characterization of variations in genome structure in the banana plant. A BAC (Bacterial Artificial Chromosome) library constructed from the cultivar Calcutta 4 (AA) is used for this purpose. This research will clarify the relative structure of banana cultivars and the impact of translocations on their diversity, and open up new ways to improvement. (Texte intégral)
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