Karyotypical studies of two maize races from Northeast Argentine (NEA):

REALINI MF, L POGGIO, GE GONZALEZ

Maize Genetics Cooperation Newsletter

University of Missouri

Año: 2013 vol. 87 p. 1 - 6

1090-4573

Knobs heterochromatic blocks occur in all Zea species with 2n = 20, varying in sizeand number across maize races and their wild relatives (Kato, Mass. Agric. Exp. Stn. Bull.635: 1-185, 1976; McClintock et al., Colegio de Postgraduados, Chapingo, México, 1981;González & Poggio, Genome 54: 26?32, 2011; Poggio et al., Cytogenet. Genome Res. 109:259?267, 2005). Variation in DNA content has been proposed to be principally due todifferences in the amount of heterochromatin, which is mainly located in distal knobs(Laurie & Bennett, Herediy 55:307-313, 1985; Poggio et al., Ann. Bot. 82:115-117, 1998).These structures can be observed as subtelomeric bands by DAPI-banding, and usingFluorescent In Situ Hybridization (FISH) (González et al., Chrom. Res. 14: 629-635, 2006).Knobs have been described as highly repeated tandem arrays of 180-bp and TR-1 (350 bp)sequences, both repeated in different proportions constituting different knobs (Dennis &Peacock, J. Mol. Evol. 20: 341-350, 1984; Ananiev et al., Proc. Natl. Acad. Sci. 95: 10785-10790, 1998).