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Titre :	Isozyme diversity in Iris cristata and the threatened glacial endemic I. lacustris (Iridaceae)
Type de document :	Tiré à part de revue
Auteurs :	Gary L. Hannan ; Michael W. Orick
Année de publication :	2000
Importance :	293-301
Langues :	Français (fre)
Catégories :	[CBNPMP-Thématique] Génétique et écologie (dynamique, démographique, sélection) [CBNPMP-Thématique] Variabilité en protéines, polymorphisme enzymatique
Mots-clés :	Iris cristata  Iris lacustris
Résumé :	Iris cristata and I. lacustris differ markedly in geographic distribution, glacial history of current ranges, and ecology. We hypothesized that I. cristata, a widespread species of unglaciated regions of eastern North America, would exhibit genetic diversity typical of other widespread plant species, whereas the threatened I. lacustris, which occupies glaciated habitats on Great Lakes shorelines, would display little genetic variation. Iris lacustris lacked detectable polymorphisms in 18 isozyme loci, although we found evidence of possible incomplete gene silencing in four additional loci in some populations. In contrast, I. cristata was polymorphic at 73% of 15 loci examined, with an average of three alleles per locus. Genetic diversity (H(e)) was 0.231. All species-level and population-level estimates of genetic diversity were higher than averages for plants having comparable life history traits. Nearly 98% of the total genetic diversity in I. cristata was apportioned within populations, and heterozygosity and fixation estimates suggest a high level of outcrossing in this species (t = 1.265). The long-lived perennial habit and high outcrossing rate in stable populations are proposed as factors contributing to high genetic diversity in I. cristata. The data are consistent with an hypothesis of a recent origin of I. lacustris from a very limited I. cristata gene pool exacerbated by repeated bottlenecks and founder effects as I. lacustris populations were displaced by lake-level changes over the past 11 000 yr.
Lien pérenne :	DOI : 10.2307/2656625
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=130359

Isozyme diversity in Iris cristata and the threatened glacial endemic I. lacustris (Iridaceae) [Tiré à part de revue] / Gary L. Hannan ; Michael W. Orick . - 2000 . - 293-301.
Langues : Français (fre)

Catégories :	[CBNPMP-Thématique] Génétique et écologie (dynamique, démographique, sélection) [CBNPMP-Thématique] Variabilité en protéines, polymorphisme enzymatique
Mots-clés :	Iris cristata  Iris lacustris
Résumé :	Iris cristata and I. lacustris differ markedly in geographic distribution, glacial history of current ranges, and ecology. We hypothesized that I. cristata, a widespread species of unglaciated regions of eastern North America, would exhibit genetic diversity typical of other widespread plant species, whereas the threatened I. lacustris, which occupies glaciated habitats on Great Lakes shorelines, would display little genetic variation. Iris lacustris lacked detectable polymorphisms in 18 isozyme loci, although we found evidence of possible incomplete gene silencing in four additional loci in some populations. In contrast, I. cristata was polymorphic at 73% of 15 loci examined, with an average of three alleles per locus. Genetic diversity (H(e)) was 0.231. All species-level and population-level estimates of genetic diversity were higher than averages for plants having comparable life history traits. Nearly 98% of the total genetic diversity in I. cristata was apportioned within populations, and heterozygosity and fixation estimates suggest a high level of outcrossing in this species (t = 1.265). The long-lived perennial habit and high outcrossing rate in stable populations are proposed as factors contributing to high genetic diversity in I. cristata. The data are consistent with an hypothesis of a recent origin of I. lacustris from a very limited I. cristata gene pool exacerbated by repeated bottlenecks and founder effects as I. lacustris populations were displaced by lake-level changes over the past 11 000 yr.
Lien pérenne :	DOI : 10.2307/2656625
Permalink :	https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=130359