CHROMOSOME IDENTIFICATION AND COMPARATIVE MOLECULAR CYTOGENETIC MAPPING BASED ON OLIGO-FISH IN MODEL PLANTS
FISH, oligonucleotide, oligo-probes, maize, karyotype, pachytene
The accurate chromosome identification is the most important fundament for the success on
cytogenetics research. Different strategies based on conventional and molecular cytogenetics
analyses have been used to create chromosome-specific marks to unambiguously distinguish
homologous chromosomes pairs from each other. A variable fluorescent in situ hybridization
probes were generated based on large genomic insertions, single DNA repeats and single copy
genes. Even though these strategies are useful, they are time-consuming, labor-intensive and
have low repeatability across different laboratories. Oligonucleotides-based FISH probes,
recently developed, showed to be a repeatable, cheap and easy methodology for chromosome
identification. In our current study, we showed that a barcode system based on oligo-FISH
probes can be used to identify all 20 chromosomes of corn in metaphase chromosome spreads
and meiotic pachytene stage. The probes designed for corn generated a similar FISH signals
pattern in its relatives chromosomes, showing this is a powerful method for evolutionary studies.
We discussed about some karyotype variations related with knobs length and distributions, and a
paracentric inversion of chromosome 4 of Zea luxurians.