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Title: A multivalent three-point linkage analysis model of autotetraploids

item LU, YAFEI - Beijing Forestry University
item YANG, XIAOXIA - Beijing Forestry University
item TONG, CHUNFA - Pennsylvania State University
item LI, XIN - Beijing Forestry University
item FENG, SISI - Beijing Forestry University
item WANG, ZHONG - Beijing Forestry University
item PANG, XIAOMING - Beijing Forestry University
item WANG, YAQUN - Pennsylvania State University
item WANG, NINGTAO - Pennsylvania State University
item Tobias, Christian
item WU, RONGLING - Pennsylvania State University

Submitted to: Briefings in Bioinformatics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2012
Publication Date: 9/17/2012
Citation: Lu, Y., Yang, X., Tong, C., Li, X., Feng, S., Wang, Z., Pang, X., Wang, Y., Wang, N., Tobias, C.M., Wu, R. 2012. A multivalent three-point linkage analysis model of autotetraploids. Briefings in Bioinformatics. doi:10.1093/bib/bbs051.

Interpretive Summary: Collectively, these results provide a complete description of switchgrass chromosomes. Furthermore, results indicate genetic divergence between the distinct copies of it’s duplicated genome and allow for the classification of switchgrass plants belonging to divergent genetic pools. Furthermore, the chromosome structure and analysis of switchgrass provides a physical framework for genetic and genomic studies

Technical Abstract: A cytogenetic study was conducted on a dihaploid individual (2n'='2X'='18) of switchgrass to establish a chromosome karyotype. Size differences, condensation patterns, and arm-length ratios were used as identifying features and fluorescence in-situ hybridization (FISH) assigned 5S and 45S rDNA loci to chromosomes 7 and 2 respectively. Both a maize CentC and a native switchgrass centromeric repeat (PviCentC) that shared 73% sequence identity demonstrated a strong signal on chromosome 3. However, only the PviCentC probe labeled the centromeres of all chromosomes. Unexpected PviCentC and 5S rDNA hybidization patterns were consistent with severe reduction or total deletion of these repeats in one subgenome. These patterns were maintained in tetraploid and octoploid individuals. The 45S rDNA repeat produced the expected number of loci in dihaploid, tetraploid and octoploid individuals. Differences observed at the 5S rDNA loci between the upland and lowland ecotypes of switchgrass provided a basis for distinguishing these subpopulations.