Inbreeding is bound to occur in all finite size populations sooner or later. In very small populations, the rate of inbreeding might reach levels where the negative genetic consequences of this phenomenon start to manifest themselves in inbreeding depression. However, without access to pedigrees, the actual inbreeding events and rate of inbreeding can be hard to deduce. Molecular marker based inference about levels of inbreeding is nowadays a commonplace practice, despite of the fact that number of technical caveats undermine such inference.
By making use of available pedigree information from a long-term study of Siberian jay population, Jussi compared the correlation between pedigree and marker based estimates of individual ‘inbreeding coefficients’. Only handful of similar studies have conducted so far, and Jussi’s results – published on the pages of Conservation Genetics – concur with the earlier results and theoretical expectations: the marker and actual pedigree based estimates of inbreeding are only weakly correlated even in this quite large data set.
And yes, yet another sad thing here is the time it takes for some journals to get their articles printed: this ms was submitted in August 2007, finally accepted and published online in April 2008. The print version is to appear at earliest in April 2009.
Check also the other recent advances Siberian jay genetics here and here.
Alho J.S., Lillandt B.-G., Jaari S., Merilä J. (2009) Multilocus heterozygosity and inbreeding in the Siberian jay. Conservation Genetics, in press. doi:10.1007/s10592-008-9588-z



2 Comments
The inbreeding coefficient estimation based on pedigree is quite rare, I think, because (i) the unavailability of pedigrees in natural populations, (ii) the population sizes are small and (iii) there are less generations to be tracked. But in domestic animals, as in the Finnsheep for exmaple, estimation of their inbreeding coefficient and effctive population size has recently been published. See http://jas.fass.org/cgi/content/abstract/jas.2008-0848v1
Believe it or not, this preprint has finally gone to print in the June issue of the Conservation Genetics (Conserv Genet (2009) 10:605–609).
http://www.springerlink.com/content/033064j833878312/fulltext.pdf