The Effects Of Inbreeding In Species Evolution

In small species under deleterious mutations,accumulative homozygosity can result in the species extinct,which is associated with the inbreeding.Inbreeding depression and small species extinct is a research hotspot of the scholars.Penna model is the important tools to study the phenomena in zoology,but the strict definition of inbreeding in this Model has not been defined and the effects of inbreeding and outbreeding are not specific,so the study of inbreeding in Penna is very significant.With more and more small species turn out,we should pay more attention to them.This paper,we present the definition of inbreeding,add family and outbreeding strategy to Standard sexual Penna model,study the effects of inbreeding in this model.We discuss the effect of inbreeding in small and large species,and also measure average of heterozygosity relate to age and similarity of genes by two different Hamming distances.What's more,we discuss the factors which affect H₁ and H₂,and emphatically discuss the effects of environmental capacity.We also bring up some methods to rescue the species based on the different reasons of extinction in our model.The results show the effects of outbreeding in small species are more obvious, outbreeding strategy improves the heterozygosity and reduces similarity of genes.If we only considered the deleterious mutation,outbreeding decreases the speed of extinction.H₁ and H₂ approach an asymptotic distribution when the environmental capacity becomes very large,H₁ increases direct proportion with age except for aged individuals and the distribution of H₂ is similar to the normal distribution.We bring up inbreeding statistical model to analyze the effects of environmental capacity on the inbreeding depression and in this model the average of inbreeding is defined.The results show the average of inbreeding approach an equilibrium when the number of individuals reach an equilibrium and the value of equilibrium decreases when the environmental capacity arises,which proves the effects of inbreeding in small species are more obvious.