Probabilistic Allele Calling to Improve Population Size Estimates from 
Non-Invasive Genetic Mark-Recapture Analysis.

Accurate estimates of population sizes are necessary to help researchers 
understand how wildlife populations are changing over time.  When sampling 
rare or elusive species, the limits of traditional mark-recapture methods 
of population size estimation can sometimes be addressed by utilizing 
non-invasive genetic mark-recapture methods. Using this method, 
non-invasive genetic samples, such as hair or scat, are collected and 
genotyped at multiple microsatellite markers.  One major problem 
introduced by non-invasive genetic methods is the overestimation of 
population sizes due to genotyping errors.  To achieve better population 
size estimates, I propose a new probabilistic allele calling method that 
assigns probabilities to possible allele calls based on electropherogram 
peak heights.  Using computer simulations, I compared the new allele 
calling method to a traditional allele calling method.  Estimates from the 
probabilistic method were less biased and more precise than the tra!
 ditional method in almost all cases.  This new method of analyzing 
non-invasive genetic mark-recapture data has the potential to allow 
wildlife population sizes to be accurately estimated using non-invasive 
methods in less time and at lower cost than current methods.