Authors:J. M. Greenwood-Lee, P. D. Taylor, and D. Haig
We develop a general inclusive fitness model for genetic evolution at an imprinted locus – one at which selection is allowed to act conditionally upon parental origin of the gene. In many cases of interest, such genes affect the fitness of relatives, particularly sibs. We formulate a matrilineal and patrilineal inclusive fitness and show that these can be used to describe the dynamics of change in mean expression levels. We classify and analyze the stability of equilibrium points and apply our results to some examples that have appeared in the literature, multiple paternity of a female's offspring, the “ovarian time-bomb,” and loss-of-function mutations.
Very little attention has been given in the literature to the interesting question of how to handle relatedness in finite populations. The main problem is that a finite population is never really ieat equilibriuml. in that it represents just one realization of an infinite assemblage of possible allelic distributions. A recent paper of Rousset and Billiard (manu- script) provides coefficients which, if used in inclusive fitness models under conditions of weak selection, give us a measure of average allele frequency change where the average is taken over all such realizations. Their coefficients are expressed in terms of identity in state, and an alternative formulation (Taylor and Day, manuscript) in terms of coefficients of consanguinity permits the calculation of relatedness in simple cases from pedigree analysis. Here we implement these calculations in a finite asexual haploid population with either a deme structure or a one-dimensional stepping-stone structure and verify our results with numerical simulations in small populations. Our simulations al- low us to investigate the dependence of relatedness on allele frequency, and our results here agree qualitatively with those obtained by Rousset and Billiard. Finally, we examine a model of altruism in a deme-structured population to verify numerically that our relatedness coefficients provide a correct measure of allele frequency change.
Authors:J. K. Hartwell, P. L. Winston, D. J. Marts, L. D. Moore-McAteer, and S. C. Taylor
Some United States Department of Energy-owned spent fuel elements from foreign research reactors (FRRs) are presently being shipped from the reactor location to the US for storage at the Idaho National Engineering and Environmental Laboratory (INEEL). Two cadmium zinc telluride detector-based gamma-ray spectrometers have been developed to confirm the irradiation status of these fuels. One spectrometer is configured to operate underwater in the spent fuel pool of the shipping location, while the other is configured to interrogate elements on receipt in the dry transfer cell at the INEEL’s Interim Fuel Storage Facility (IFSF) Both units have been operationally tested at the INEEL.