Quantifying time-inhomogeneous stochastic introgression processes with hazard rates

• Autor(a) principal: Ghosh, Atiyo
• Data de Publicação: 2012
• Outros Autores: Serra, Maria Conceição, Haccou, Patsy
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/21426
• topic: Branching process; Invasion; Transgene; Risk management; Random environment; Science & Technology

Introgression is the permanent incorporation of genes from one population into another through hybridization and backcrossing. It is currently of particular concern as a possible mechanism for the spread of modi ed crop genes to wild populations. The hazard rate is the probability per time unit that such an escape takes place, given that it has not happened before. It is a quantitative measure of introgression risk that takes the stochastic elements inherent in introgression processes into account. We present a methodology to calculate the hazard rate for situations with time-varying gene ow from a crop to a large recipient wild population. As an illustration, several types of time-inhomogeneity are examined, including deterministic periodicity as well as random variation. Furthermore, we examine the e ects of an extended tness bottleneck of hybrids and backcrosses in combination with time-varying gene ow. It is found that bottlenecks decrease the hazard rate, but also slow down and delay its changes in reaction to changes in gene ow. Furthermore, we nd that random variation in gene ow generates a lower hazard rate than analogous deterministic variation. We discuss the implications of our ndings for crop management and introgression risk assessment.