The Gene Pool in Cross-Fertilizing Populations 



227 



SUMMARY AND CONCLUSIONS 



The gametes which function to produce the next generation in cross-fertilizing populations 

 comprise a gene pool. If the population (gene pool) size is very large, if mutation does not 

 occur in any direction preferentially, if there is no differential selection for genotypes, and 

 if migrants are genotypically just like the natives, the gene pool in successive generations 

 will remain forever unchanged, as will also the relative frequencies of genotypes. However, 

 if any of these conditions fails to obtain, there will be a shift in the nature of the gene pool, 

 that is, gene frequencies will change, and so will the frequencies of different genotypes, until 

 a new equilibrium is attained. 



It is suggested that not only species formation, but all of biological evolution is based 

 upon changes in the gene pool. 



REFERENCES 



Dobzhansky, Th., Evolution, Genetics, and Man, New York, John Wiley & Sons, 1955. 



Dobzhansky, Th., Genetics and the Origin of Species, 3rd Ed., New York, Columbia Univer- 

 sity Press, 1951. 



Hardy, G. H., "Mendelian Proportions in a Mixed Population," Science, 28:49-50, 1908. 

 Reprinted in Classic Papers in Genetics, Peters, J. A. (Ed.), Englewood Cliffs, N.J., 

 Prentice-Hall, 1959, pp. 60 62, and in Great Experiments in Biology, Gabriel, M. L., 

 and S. Fogel (Eds.), Englewood Cliffs, N.J., Prentice-Hall, 1955, pp. 295-297. 



Li, C. C, Human Genetics, New York, McGraw-Hill, 1961. 



Theodosius Dobzhansky in 1957. 



Sewall Wright is noted for his research in phys- 

 iological genetics and in tlie mathematics of popu- 

 lation genetics. Photograph was taken in 1954. 



