FISH-Mapping Pachytene Chromosomes Of Coffee (Coffea L.)

Date: Sunday, January 13, 2013
Time: 5:10 PM
Room: Sunset
Ana Amélia Sanchez Iacia , Instituto Agronomico, Campinas, Brazil
Cecília A.F. Pinto-Maglio , Instituto Agronomico, Campinas, Brazil, Campinas, Brazil
Fluorescent in situ hybridization (FISH) provides the most direct way of physically mapping DNA sequences on chromosomes. FISH-mapping to meiotic chromosomes at pachytene is an important tool in plant cytogenetic research as it provides good resolution measurements of physical distances. We have been able to overcome the most difficulties to apply a specific method for FISH on pachytene chromosomes of coffee plants (Coffea L.). Meiotic chromosomes observed at pachytene stage in pollen mother cells (PMCs) of coffee are more suitable for FISH physical mapping because they are about 30 times longer than their somatic counterparts. They also provide additional cytological markers like a pattern of distal euchromatin and pericentromeric heterochromatin regions. For the first time we observed hybridization signals on coffee pachytene chromosomes by FISH technique using a repetitive sequence as probe. The method involves some procedures for obtain suitable pachytene chromosomes. Slides with 80% of the PMCs with hybridization signals on bivalents were obtained. The method developed showed no genotype dependency as we registered the presence of hybridization signals in different coffee plants. The use of this method expands the possibilities for high definition physical mapping of coffee chromosomes.