Soraya Leal-Bertioli, Kenta Shirasawa, Brian Abernathy, Marcio Moretzsohn, Carolina Chavarro, Josh Clevenger, Peggy Ozias-Akins, Scott Jackson and David Bertioli
Genetics April 1, 2015 vol. 199 no. 4 1093-1105
http://www.genetics.org/content/199/4/1093.abstract?etoc
Abstract
Arachis hypogaea L. (cultivated peanut) is an allotetraploid (2n = 4x = 40) with an AABB genome type. Based on cytogenetic studies it has been assumed that peanut and wild-derived induced AABB allotetraploids have classic allotetraploid genetic behavior with diploid-like disomic recombination only between homologous chromosomes, at the exclusion of recombination between homeologous chromosomes. Using this assumption, numerous linkage map and quantitative trait loci studies have been carried out. Here, with a systematic analysis of genotyping and gene expression data, we show that this assumption is not entirely valid. In fact, autotetraploid-like tetrasomic recombination is surprisingly frequent in recombinant inbred lines generated from a cross of cultivated peanut and an induced allotetraploid derived from peanut’s most probable ancestral species. We suggest that a better, more predictive genetic model for peanut is that of a “segmental allotetraploid” with partly disomic, partly tetrasomic genetic behavior. This intermediate genetic behavior has probably had a previously overseen, but significant, impact on the genome and genetics of cultivated peanut.
![Tetrasomic Recombination Is Surprisingly Frequent in Allotetraploid Arachis](/Images_upload/images/New Picture (20)(14).png)
Figure 2 Example of a plot of signal intensities generated using GenomeStudio from an “intergenomic” SNP assay on the RIL population derived from A. hypogaea × [A. ipaënsis × A. duranensis]4x. These parentals are indicated by orange and yellow arrows, respectively. Diploid controls for A. duranensis and A. ipaënsis are shown as green and red arrows, respectively. For the classic allotetraploid genetic model, no recombinants are expected, but here four progenies have tetraplex/nulliplex genotypes. These genotypes can arise only from tetrasomic recombination. These intergenomic assays can score all genotypes resultant from tetrasomic recombination.
|
[ Other News ]___________________________________________________
|