Paper: Testing for clonal propagation

From: Robert Karl Stonjek (rstonjek_at_bigpond.net.au)
Date: 01/27/05 

Date: Thu, 27 Jan 2005 16:50:39 -0500 (EST)

Testing for clonal propagation

H-R Gregorius

Institut für Forstgenetik und Forstpflanzenzüchtung, Universität Göttingen
Büsgenweg 2, 37077 Göttingen, Germany
Correspondence to: H-R Gregorius, Institut für Forstgenetik und
Forstpflanzenzüchtung, Universität Göttingen Büsgenweg 2, 37077 Göttingen,
Germany.

Abstract

The conceptual basis for testing clonal propagation is reconsidered with the
result that two steps need to be distinguished clearly: (1) specification of
the characteristics of multilocus genotype frequencies that result from
sexual reproduction together with the kinds of deviations from these
characteristics that are produced by clonal propagation, and (2) a
statistical method for detecting these deviations in random samples. It is
pointed out that a meaningful characterization of sexual reproduction
reflects the association of genes in (multilocus) genotypes within the
bounds set by the underlying gene frequencies. An appropriate measure of
relative gene association is developed which is equivalent to a multilocus
generalization of the standardized gametic disequilibrium (linkage
disequilibrium). Its application to the characterization of sexually
produced multilocus genotypes is demonstrated. The resulting hypothesis on
the frequency of a sexually produced genotype is tested with the help of the
(significance) probability of obtaining at least two copies of the genotype
in question in a random sample of a given size. If at least two copies of
the genotype are observed in a sample, and if the probability is
significant, then the hypothesis of sexual reproduction is rejected in favor
of the assumption that all copies of the genotype belong to the same clone.
Common testing approaches rest on the hypothesis of completely independent
association of genes in genotypes and on the (significance) probability of
obtaining at least as many copies of a genotype as observed in a sample. The
validity of these approaches is discussed in relation to the above
considerations and recommendations are set out for conducting appropriate
tests.

Heredity (2005) 94, 173-179. doi:10.1038/sj.hdy.6800593
Published online 3 November 2004

Abstract and full text links at Nature Genetics
http://www.nature.com/cgi-taf/DynaPage.taf?file=/hdy/journal/v94/n2/abs/6800593a.html

Posted by
Robert Karl Stonjek

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