Classifying seedlots of Picea sitchensis and P. glauca in zones of introgression using restriction analysis of chloroplast DNA

Abstract

Chloroplast DNA (cpDNA) restriction analysis was used to classify five reforestation seedlots as to species. The material included two Sitka spruce (Picea sitchensis (Bong.) Carr.), one white spruce (P. glauca (Moench) Voss) from interior British Columbia, and two putative hybrid seedlots from the coast-interior introgression zone in British Columbia. The cpDNA patterns generated by Bam-HI and Bc1-I from individual trees of Sitka spruce, white spruce, western white spruce (P. glauca var. albertiana (S. Brown)), and Engelmann spruce (P. engelmanni (Parry)) were species-specific. They were used as reference patterns for comparisons. In addition, two controlled crosses between white and Sitka spruce were analyzed to demonstrate the paternal inheritance of cpDNA in spruces. The cpDNA restriction patterns for the five seedlots were obtained from composite samples of seedlings from each lot and compared to the typical cpDNA patterns of each species. Restriction patterns for the two Sitka spruce seedlots agreed with those from the Sitka spruce tree, while patterns for the white spruce seedlots from British Columbia agreed with those from the white spruce tree, lacking evidence of any Engelmann spruce component in the sample. On the other hand, one putative hybrid seedlot showed cpDNA patterns similar to white spruce while the other showed fragments unique to both Sitka and white spruce, indicating that this was a hybrid seedlot. The analysis of cpDNA restriction polymorphism has proven to be an effective tool for classifying seedlots in regions of introgression. To our knowledge, these results provide the first demonstration of the use of cpDNA analysis for solving practical forestry problems.

Assessment of the Genetic Diversity in Forest Tree Populations Using Molecular Markers

“…However, the problem of these biochemical marker assays is that they are affected by plant phenological stage and their limited availability, and therefore, they would never allow for a genome-wide scan of variability (as only 0.1% of the total variation is detectable by this technique, [19]). An invaluable alternative offered DNA-based markers, such as restriction fragment length polymorphism (RFLPs) [20][21][22]. Finally, the possibility to rapidly amplify specific DNA fragments in vitro via polymerase chain reaction (PCR) [23] revolutionized the generation of molecular markers, leading to diverse sets of diagnostic DNA-marker systems with or without a priori sequence knowledge, such as random amplified polymorphic DNA (a.k.a RAPD) [24], amplified fragment length polymorphism (a.k.a AFLP) [25], simple sequence repeats (a.k.a SSRs or microsatellites) [26], single nucleotide polymorphisms (a.k.a SNPs) [27,28] and variations thereof [29,30].…”

Allozyme and chloroplast DNA variation in Italian and Greek populations of Pinus leucodermis

“…Both views are mainly based on morphological and crossability analyses. Recently, isozyme and chioroplast DNA (cpDNA) analyses have been used to reconstruct the phylogenetic relationships among conifer forest tree species (Sigurgeirsson & Szmidt, 1988;Wang & Szmidt, 1990;Shurkhal et at., 1992;Wagner et at., 1992). Most cpDNA analyses conducted to date have examined restriction fragment length polymorphisms (RFLPs) over the entire chloroplast genome or nucleotide sequences of a single gene.…”

Chromosome banding in <i>Picea</i> IV. Comparative karyotype analysis of fluorescent band patterns in 25 taxa

“…Natural hybridization and introgression in sympatric area for examples between P. mariana and P. rubens (Perron and Bousquet 1997) and P. sitchensis and P. glauca (Szmidt et al 1988), and other combination (Sutton et al 1991;Rajora and Dancik 2000), were reported. The introgression increases variability of populations or species.…”