Michalak de Jimenez, M.K., Bassi, F.M., Ghavami, F., Simons, K., Dizon, R., Seetan, R.I., Alnemer, L.M., Denton, A.M., Doğramacı, M., Šimková, H., Doležel, J., Seth, K., Luo, M.-C., Dvorak, J., Gu, Y.Q., Kianian, S.F.
FUNCTIONAL & INTEGRATIVE GENOMICS
13:
19-32,
2013
Keywords:
Species cytoplasm specific, Wheat Zapper, Synteny, Paleofusion, Alloplasmic, Cytoplasm substitution
Abstract:
The species cytoplasm specific (scs) genes affect
nuclear-cytoplasmic interactions in interspecific hybrids. A
radiation hybrid (RH) mapping population of 188 individuals
was employed to refine the location of the scsae locus on
Triticum aestivum chromosome 1D. “Wheat Zapper,” a
comparative genomics tool, was used to predict synteny between
wheat chromosome 1D, Oryza sativa, Brachypodium
distachyon, and Sorghum bicolor. A total of 57 markers were
developed based on synteny or literature and genotyped to
produce a RH map spanning 205.2 cR. A test-cross methodology
was devised for phenotyping of RH progenies, and
through forward genetic, the scsae locus was pinpointed to a
1.1 Mb-segment containing eight genes. Further, the high
resolution provided by RH mapping, combined with
chromosome-wise synteny analysis, located the ancestral point
of fusion between the telomeric and centromeric repeats of two
paleochromosomes that originated chromosome 1D. Also, it
indicated that the centromere of this chromosome is likely the
result of a neocentromerization event, rather than the conservation
of an ancestral centromere as previously believed.
Interestingly, location of scs locus in the vicinity of paleofusion
is not associated with the expected disruption of synteny, but
rather with a good degree of conservation across grass species.
Indeed, these observations advocate the evolutionary importance
of this locus as suggested by “Maan’s scs hypothesis.”
Fulltext: contact IEB authors
IEB authors: Jaroslav Doležel,
Hana Šimková
Čeština
English