Wt. Sinclair et al., MULTIPLE ORIGINS FOR SCOTS PINE (PINUS-SYLVESTRIS L) IN SCOTLAND - EVIDENCE FROM MITOCHONDRIAL-DNA VARIATION, Heredity, 80, 1998, pp. 233-240
Data from the pollen record and from two forms of nuclear genetic mark
ers suggest that present-day populations of Scots pine (Pinus sylvestr
is L.) in Scotland were derived from more than one refugium after glac
iation. In order to clarify this issue, genetic variation for maternal
ly inherited mitochondrial DNA (mtDNA) was studied in 466 trees sample
d from 20 natural populations in Scotland. A homologous probe for the
cox1 mitochondrial gene of P. sylvestris was constructed and used to d
etect mtDNA RFLP variation. Two common (a and b) and one rare RFLP var
iant (c) were distinguished. Evidence from segregation patterns of var
iants within a polymorphic population was consistent with maternal inh
eritance of the RFLP variation. A survey of Scottish populations indic
ates that mitotype a is present at all sites, but that mitotype b is c
onfined to three western populations. Genetic differentiation for mtDN
A, which migrates solely by seed is much greater (F-ST(m) = 0.370) tha
n for nuclear markers (F-ST(b) = 0.028) which are dispersed by both po
llen and seed. The geographical distribution of mitotype b in western
Scotland, and its absence from populations in northern France and Germ
any, suggest that P. sylvestris has been derived not only from contine
ntal Europe via England, but also by migration from a western refugium
, probably in Ireland or western France.