INVESTIGADORES
SOUTO cintia Paola
artículos
Título:
Effects of population disjunction on isozyme variation in the widespread Pilgerodendron uvíferum
Autor/es:
PREMOLI, A. C.; SOUTO, C. P.; ALLNUT, T.; NEWTON, A.
Revista:
HEREDITY
Referencias:
Año: 2001 vol. 87 p. 337 - 343
ISSN:
0018-067X
Resumen:
Geographical range is considered a good predictor of the levels of isozyme variation in plants.
Widespread species, often consisting of historically larger and more continuous populations, maintain
higher polymorphism and are less aected by drift, which tends to erode genetic variation in more
geographically restricted species. However, widespread species occurring in small and disjunct
populations may not ®t this pattern. In this study we examined genetic variation in Pilgerodendron
uviferum, a conifer endemic to temperate forests of southern South America, and is such a widespread
and habitat-restricted species. Twenty populations along the whole range of Pilgerodendron were
analysed by isozyme electrophoresis to resolve 14 putative genetic loci. Eleven were polymorphic in at
least one population although only six of them were polymorphic in more than one population. We
found reduced within-population levels of isozyme variation, with only 11% polymorphic loci
(0.95 criterion), 1.2 mean number of alleles per locus, and mean observed and expected
heterozygosities of 0.024 and 0.033, respectively. Most genetic diversity was found within populations
(HT.0.039, HS.0.033, FST 15%). Greater polymorphism and lower divergence was estimated in the
more geographically restricted and closely related Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone.Pilgerodendron
uviferum, a conifer endemic to temperate forests of southern South America, and is such a widespread
and habitat-restricted species. Twenty populations along the whole range of Pilgerodendron were
analysed by isozyme electrophoresis to resolve 14 putative genetic loci. Eleven were polymorphic in at
least one population although only six of them were polymorphic in more than one population. We
found reduced within-population levels of isozyme variation, with only 11% polymorphic loci
(0.95 criterion), 1.2 mean number of alleles per locus, and mean observed and expected
heterozygosities of 0.024 and 0.033, respectively. Most genetic diversity was found within populations
(HT.0.039, HS.0.033, FST 15%). Greater polymorphism and lower divergence was estimated in the
more geographically restricted and closely related Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone., a conifer endemic to temperate forests of southern South America, and is such a widespread
and habitat-restricted species. Twenty populations along the whole range of Pilgerodendron were
analysed by isozyme electrophoresis to resolve 14 putative genetic loci. Eleven were polymorphic in at
least one population although only six of them were polymorphic in more than one population. We
found reduced within-population levels of isozyme variation, with only 11% polymorphic loci
(0.95 criterion), 1.2 mean number of alleles per locus, and mean observed and expected
heterozygosities of 0.024 and 0.033, respectively. Most genetic diversity was found within populations
(HT.0.039, HS.0.033, FST 15%). Greater polymorphism and lower divergence was estimated in the
more geographically restricted and closely related Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone.Pilgerodendron were
analysed by isozyme electrophoresis to resolve 14 putative genetic loci. Eleven were polymorphic in at
least one population although only six of them were polymorphic in more than one population. We
found reduced within-population levels of isozyme variation, with only 11% polymorphic loci
(0.95 criterion), 1.2 mean number of alleles per locus, and mean observed and expected
heterozygosities of 0.024 and 0.033, respectively. Most genetic diversity was found within populations
(HT.0.039, HS.0.033, FST 15%). Greater polymorphism and lower divergence was estimated in the
more geographically restricted and closely related Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone.HT.0.039, HS.0.033, FST 15%). Greater polymorphism and lower divergence was estimated in the
more geographically restricted and closely related Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone.Fitzroya. Thus, total range, in combination with
information on the degree of among-population isolation, may be a better predictor of the levels of
polymorphism than range size alone.