CYTOLOGICAL FEATURES OF PEANUT GENOME

SEIJO, J.G.; SILVESTRI, M.C.; SAMOLUK, S.; CHALUP, L.; ORTIZ, A.M.; ROBLEDO, G.; LAVIA, G.I.

The Peanut Genome

Springer

Año: 2017; p. 37 - 52

This chapter aims to update the chromosomal features evaluated byclassical and molecular cytogenetic techniques. Karyotype variabilitydetected within and among species was very useful to unravel thetaxonomy of the genus and to establish relationships among species. Thischapter includes analyses of chromosome morphology, heterochromatin,rDNA loci, as well as dispersed and clustered repetitive sequences.A critical review of the genome sizes of Arachis species is also provided.The usefulness of chromosome data is presented in three examples. Thefirst one deals with the origin of the cultivated peanut. Molecularcytogenetics evidenced that the varieties of A. hypogaea may have had asingle genetic origin, that A. monticola is a direct tetraploid ancestor ofpeanut, and that A. duranensis (A genome) and A. ipaënsis (B genome)are the diploid progenitors of the AABB tetraploids. The second onepointed to the analysis of the origin of the rhizomatous tetraploids andtheir relation to the unique diploid species (A. burkartii) of sectionRhizomatosae. The cytogenetic data suggest that A. burkartii has to bediscarded as a genome donor of the tetraploids, and that the latter mayhave had independent origins involving different species. The third oneconcerns the species of section Arachis, and how the chromosome dataaided in the establishment of the genome groups (A, B, D, F, G, and K).