Department of Cell and Molecular Biology, Genetic Section, Laboratory of
Genetics Analysis in Domestic Animals, Faculty of Veterinary, UDELAR, A.
Lasplaces 1550 CP 11600, Montevideo, Uruguay.
Fragile sites (FS) seem to play a role in genome instability and may be involved
in karyotype evolution and chromosome aberrations. The majority of common
fragile sites are induced by aphidicolin. Aphidicolin was used at two different
concentrations (0.15 and 0.30 microM) to study the occurrence of FS in the
cattle karyotype. In this paper, a map of aphidicolin induced break points and
fragile sites in cattle chromosomes was constructed. The statistical analysis
indicated that any band with three or more breaks was significantly damaged
(P<0.05). According to this result, 30 of the 72 different break points observed
were scored as fragile sites. The Pearson correlation test showed a positive
association between chromosome length and the number of fragile sites (r=0.54).
On the contrary, 21 FS were identified on negative R bands while 9 FS were
located on positive R bands.