Analysis of Sitka spruce: interior spruce introgression in British Columbia using cytoplasmic and nuclear DNA probes.
1994
Sutton B.C.S. | Pritchard S.C. | Gawley J.R. | Newton C.H.
Restriction fragment length polymorphisms of the nuclear ribosomal RNA genes were used to define species-specific patterns for interior spruce (a complex of white spruce, Picea glauca (Moench) Voss, and Engelmann spruce, Picea engelmannii Parry) and Sitka spruce (Picea sitchensis (Bong.) Carr.) populations in British Columbia. These patterns are highly conserved among seed lots and individual trees of each species from diverse geographic origins. Both the ribosomal RNA gene probe and species-specific probes for the chloroplast and mitochondrion, described previously, were used to analyze 164 dominant trees from 19 locations in a zone of presumed Sitka-interior spruce introgression in northwestern British Columbia. Hybrid fraction was estimated from an index based on the relative abundance of polymorphic ribosomal RNA hybridizing bands for each tree and was in good agreement with the proportion of trees exhibiting either interior or Sitka spruce specific chloroplast bands. The results demonstrate that complex hybrids occur frequently in this zone, indicative of true introgression. Furthermore, the trend of variation in species mix is consistent with the topographical trends. It is anticipated that the results of this survey will be useful in defining seed transfer guidelines for reforestation of this region.
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