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Article
Low efficiency of pseudotestcross mapping design was consistent with limited genetic diversity and low heterozygosity in hoop pine (Araucaria cunninghamii, Araucariaceae)
Tree Genetics and Genomes
  • Leon J Scott, Southern Cross University
  • Mervyn Shepherd, Southern Cross University
  • D Garth Nikles, Queensland Department of Primary Industries
  • Robert J Henry, Southern Cross University
Document Type
Article
Publication Date
1-1-2005
Peer Reviewed
Peer-Reviewed
Abstract
Linkage maps were prepared for two Araucaria cunninghamii individuals (coded H15 and Gil24) using the pseudotestcross strategy in a wide interprovenance cross. The maternal map for individual H15 contains 14 linkage groups (haploid chromosome number=13), comprising 51 amplified fragment length polymorphisms (AFLP) and 1 microsatellite; 17 markers remain unlinked. The map covered 1,290 cM [Kosambi (K)], representing 89% of the estimated genome size. The paternal map for individual Gil24 was shorter, 633 cM (K), consisted of eight linkage groups, with an average interval of 19.8 cM (K). The difference in map lengths was due to the larger number of informative markers for maternal parent (52 loci compared with 25 loci in the paternal parent). There was no significant difference in map lengths once maps were corrected for different numbers of loci. Overall, the number of segregating markers identified was surprisingly low for a wide interprovenance cross in an outcrossing tree species. For AFLP, a low average of 2.2 segregating markers per primer combination was obtained, and only 4 out of 29 microsatellite loci were informative in the cross. This low level of marker variation appears to be the result of low levels of heterozygosity in the parents and low levels of genetic divergence within A. cunninghamii. This result was consistent with other recent molecular studies of A. cunninghamii that indicate that the species may have low genetic diversity and possibly experiences localised inbreeding.
Citation Information

Scott, LJ, Shepherd, M, Nikles, DG & Henry, RJ 2005, 'Low efficiency of pseudotestcross mapping design was consistent with limited genetic diversity and low heterozygosity in hoop pine (Araucaria cunninghamii, Araucariaceae', Tree Genetics and Genomes, vol. 1, no. 3, pp. 124-134.

The original publication is available at www.springerlink.com at http://dx.doi.org/10.1007/s11295-005-0022-0