X-Message-Number: 26244
From: "Basie" <>
Subject: Evidence that inbreeding is harmful to species is provided
Date: Wed, 25 May 2005 12:56:13 -0400

Inbreeding is mostly harmful to species.
"Genetic stochasticity encompasses inbreeding depression, loss of genetic 
diversity, and mutational accumulation (Frankham et al. 2002). Inbreeding is 
the most immediate and potentially damaging of these (Frankham 1995a). 
Essentially, all well-studied naturally outbreeding species show depressed 
reproductive fitness in inbred individuals; this phenomenon is known as 
inbreeding depression (Falconer and Mackay 1996, Lynch and Walsh 1998, 
Hedrick and Kalinowski 2000). This has been demonstrated in the laboratory 
(see Frankham 1995b), in zoos (Ralls et al. 1988), and in the wild (see 
Crnokrak and Roff 1999). Although some scientists have been skeptical about 
the occurrence of inbreeding depression in wild populations, compelling 
evidence for it now exists. Of 157 valid data sets across 34 taxa reviewed 
by Crnokrak and Roff (1999), 90% showed differences indicating that 
inbreeding was deleterious to reproductive fitness (Frankham 2000). " Brook, 
B. W., D. W. Tonkyn, J. J. O'Grady, and R. Frankham. 2002. Contribution of 
inbreeding to extinction risk in threatened species. Conservation Ecology 
6(1): 16. [online] URL: http://www.consecol.org/vol6/iss1/art16/


Basie  www.agingtheory.com



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