Artículo
Genome sizes in diploid and allopolyploid Arachis L. species (section Arachis)
Date
2015Registration in:
Samoluk, Sergio Sebastián, et al., 2015. Genome sizes in diploid and allopolyploid Arachis L. species (section Arachis). Genetic Resources and Crop Evolution. Berlín: Springer, vol. 62, no. 5, p. 747-763. ISSN 0925-9864.
0925-9864
Author
Samoluk, Sergio Sebastián
Chalup, Laura María Isabel
Robledo Dobladez, Germán Ariel
Seijo, José Guillermo
Institutions
Abstract
Species of section Arachis with x = 10 are
important for peanut breeding and have been organized
in five different genomes (A, B, D, F and K). The few
available estimates of the DNA content are inconsistent
and hampered the understanding of the evolutionary
trends and in decision making for genomic studies of the
group. Considering that, the objectives of this research
were to measure the DNA content for all available (26)
species and to make evolutionary inferences at the
diploid and tetraploid level for section Arachis. The 2C
values obtained by flow cytometry ranged from 2.55 to
3.22 pg among the diploid species. The annual species
belonging to different genomes tend to have different
genome sizes. However, the 2C values of the perennial
species of the A genome were distributed almost along
the whole range of genome sizes here observed. The
distribution of 2C values partially support the genome
arrangement proposed for the section. The comparisons
of 2C values with karyotype parameters suggests that
changes in DNA content have been proportionally
distributed among the chromosome arms, and that the
heterochromatic fractionwas not directly involved in that
changes. Within the A genome, the annual species has
lowerDNAcontent than the perennial ones, according to
the nucleotype hypothesis. However, the lack of significant
relationships with geoclimatic variables suggests
that there are many intrinsic factors determining particular
ecological roles of the DNA content in the different
lineages of section Arachis. The constancy of the Cx
values observed in the polyploids compared to those of
the parental species suggests that the allopolyploidization
event that originated the cultivated peanut did not
induce significant changes in the genome size.