当前位置： SCI文献检索 > MOLECULAR ECOLOGY期刊下所有文献 > Diverging patterns of mitochondrial and nuclear DNA diversity in subarctic black spruce: imprint of a founder effect associated with postglacial colonization.

Diverging patterns of mitochondrial and nuclear DNA diversity in subarctic black spruce: imprint of a founder effect associated with postglacial colonization.

Abstract：

:High-latitude ecotonal populations at the species margins may exhibit altered patterns of genetic diversity, resulting from more or less recent founder events and from bottleneck effects in response to climate oscillations. Patterns of genetic diversity were investigated in nine populations of the conifer black spruce (Picea mariana [Mill.] BSP.) in northwestern Québec, Canada, using seed-dispersed mitochondrial (mt) DNA and nuclear (nc) DNA. mtDNA diversity (mitotypes) was assessed at three loci, and ncDNA diversity was estimated for nine expressed sequence tag polymorphism (ESTP) loci. Sampling included populations from the boreal forest and the southern and northern subzones of the subarctic forest-tundra, a fire-born ecotone. For ncDNA, populations from all three vegetation zones were highly diverse with little population differentiation (thetaN = 0.014); even the northernmost populations showed no loss of rare alleles. Patterns of mitotype diversity were strikingly different: within-population diversity and population differentiation were high for boreal forest populations [expected heterozygosity per locus (HE) = 0.58 and thetaM = 0.529], but all subarctic populations were fixed for a single mitotype (HE = 0). This lack of variation suggests a founder event caused by long-distance seed establishment during postglacial colonization, consistent with palaeoecological data. The estimated movement of seeds alone (effective number of migrants per generation, NmM < 2) was much restricted compared to that estimated from nuclear variants, which including pollen movement (NmN > 17). This could account for the conservation of a founder imprint in the mtDNA of subarctic black spruce. After reduction, presumably in the early Holocene, the diversity in ncDNA would have been replenished rapidly by pollen-mediated gene flow, and maintained subsequently through vegetative layering during the current cooler period covering the last 3000 years.

journal_name

Mol Ecol

journal_title

Molecular ecology

authors

Gamache I,Jaramillo-Correa JP,Payette S,Bousquet J

doi

10.1046/j.1365-294x.2003.01800.x

subject

Has Abstract

pub_date

2003-04-01 00:00:00

pages

891-901

issue

eissn

0962-1083

issn

1365-294X

pii

1800

journal_volume

pub_type

杂志文章

在线工具

Diverging patterns of mitochondrial and nuclear DNA diversity in subarctic black spruce: imprint of a founder effect associated with postglacial colonization.