Low levels of genetic diversity in red pine confirmed by random amplified polymorphic DNA markers

Abstract

Random amplified polymorphic DNA (RAPD) markers were used to characterize genetic variation in disjunct Newfoundland populations of red pine (Pinusresinosa Ait.) for comparison with individuals from throughout the mainland range of red pine. Red pine demonstrated a largely monomorphic profile for 69 arbitrary oligonucleotide primers. DNA samples from white spruce (Piceaglauca (Moench) Voss) and black spruce (Piceamariana (Mill.) B.S.P.) that were screened together with red pine for 11 oligonucleotide primers showed abundant polymorphisms, confirming the genetic heterogeneity that characterizes these Boreal Zone spruces. Results with RAPD markers correspond with genetic diversity estimates using isozyme gene markers for both spruce species and red pine. RAPD markers provided further confirmation of low levels of genetic variation for a random sample of the red pine genome. A period of between 8000 and 10 000 years of isolation on the island of Newfoundland has resulted in very little detectable genetic differentiation of island populations from mainland populations, and the mainland populations have not recovered from losses of genetic diversity following a hypothesized genetic bottleneck that may have been experienced during glacial episodes of the Holocene. The low levels of genetic variation observed in red pine demonstrate the long time periods required for recovery following a loss of genetic diversity in long-lived, long-generation organisms like trees.