Differential Evolutionary Activity in Bryophytes

Khanna, K. R.

doi:10.1111/j.1558-5646.1964.tb01680.x

Cited by 16 publications

(6 citation statements)

References 26 publications

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“…In fact, average gene diversities within populations of R. spectabile and R. cuspidigerum were closely comparable to those for wind-pollinated, highly outcrossed pines (Guries and Ledig, 1982;Loveless and Hamrick, 1984). With the exception ofYamazaki's (1981,1984) studies, genetic variation reported in liverworts appears to be less than that in mosses, as predicted by Khanna (1964). Nei's (1972) genetic distances (below the diagonal) and genetic identities (above the diagonal) for 13 populations of P/agiomnium ciliare in the southeastern United States.…”

Section: Discussionsupporting

confidence: 51%

“…On the other hand, some researchers have argued that genetic variation in bryophyte populations may be I Permanent address: Department of Genetics, Institute of Biology, Adam Mickiewicz University, 165 Dabrowskiego, Poznan 60-594, Poland. extensive (Khanna, 1964;Longton, 1976;Smith, 1978;Wyatt, 1982Wyatt, , 1985. Their view is based on recent discoveries of extreme diversity in biochemical, physiological, and ecological properties of mosses and liverworts.…”

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HIGH LEVELS OF GENETIC VARIABILITY IN THE HAPLOID MOSS PLAGIOMNIUM CILIARE

1989

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Horizontal starch-gel electrophoresis was used to measure variability at 14 enzyme loci from 13 natural populations of the dioecious moss Plagiomnium ciliare. Overall levels of genetic polymorphism were unexpectedly high for a haploid organism. Using a 1% frequency criterion, 71% of the loci surveyed were polymorphic for the species as a whole. The number of alleles per polymorphic locus for the species as a whole was 2.82 ± 0.34 (mean ± standard error), and mean gene diversity per locus was 0.078 ± 0.035. While total gene diversity (H = 0.178) was similar to that observed for highly outcrossed diploid plants such as pines, the variance within (H = 0.098 ± 0.027) and among (D = 0.080 ± 0.033) populations was more evenly distributed than that reported for populations of conifers. Genetic distances between populations ranged from 0.0002 to 0.2064, with mosses from the Piedmont region of the southeastern United States showing less differentiation among populations than did mosses from the Appalachian Mountains. Gene diversity was much reduced in populations from disturbed, secondary forests in the Piedmont (0.058 ± 0.018) relative to those from minimally disturbed, primary forests in the mountains (0.146 ± 0.048). Intensive sampling within populations revealed heterogeneity even within small (5 × 5 cm) clumps. The discovery of high levels of genetic variability in a plant with a dominant haploid life cycle challenges the traditional view of bryophytes as a genetically depauperate group. Multipleniche selection is proposed as a possible explanation for this anomaly, but the data are also consistent with the view that allozyme polymorphisms are selectively neutral.

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Section: Discussionsupporting

confidence: 51%

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confidence: 99%

HIGH LEVELS OF GENETIC VARIABILITY IN THE HAPLOID MOSS PLAGIOMNIUM CILIARE

1989

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“…It is thought that the general inefficiency of sexual reproduction among bryophytes may lead to reduced levels of genetic variation (Khanna 1964;Crum 1972). Data on genetic variation for this species are lacking.…”

Section: Carpocephala With Young Sporophytes (Stage B)mentioning

confidence: 99%

Phenological observations and sex ratios in Marchantia chenopoda L. (Hepaticae: Marchantiaceae)

Moya

1992

BDE

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“…Because natural selection acts directly on the haploid genotype, eliminating the possibility of sheltering deleterious alleles in heterozygotes, it has been widely assumed that bryophytes have lower levels of genetic variation than other plants (Anderson, 1963;Crum, 1972). Of the two major groups, liverworts are expected to have even less genetic variation than mosses, due to their reduced capacity for sexual reproduction (Khanna, 1964;Schuster, 1966).…”

Section: Introductionmentioning

confidence: 99%

High levels of genetic variation in the haploid leafy liverwortPorella platyphyllafrom the southeastern United States

Wyatt¹,

Odrzykoski²,

Cronberg³

2005

Journal of Bryology

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The few studies that have investigated levels of genetic variation in liverworts have found very little polymorphism. Our electrophoretic data show, however, that the leafy liverwort Porella platyphylla maintains high levels of genetic variation in at least some natural populations from the southeastern United States. Within a single population from southwestern North Carolina, we detected 26 distinct multilocus genotypes and more than 80% of the enzyme loci we surveyed were polymorphic. It seems likely that earlier studies of mostly thalloid species from glaciated regions of Europe have presented a biased picture of levels of variation in liverwort populations.

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Differential Evolutionary Activity in Bryophytes

Cited by 16 publications

References 26 publications

HIGH LEVELS OF GENETIC VARIABILITY IN THE HAPLOID MOSS PLAGIOMNIUM CILIARE

HIGH LEVELS OF GENETIC VARIABILITY IN THE HAPLOID MOSS PLAGIOMNIUM CILIARE

<p><strong>Phenological observations and sex ratios in <em>Marchantia </em><em>chenopoda </em>L. (Hepaticae: Marchantiaceae)</strong></p>

High levels of genetic variation in the haploid leafy liverwortPorella platyphyllafrom the southeastern United States

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