Genetic Systems I | 173 



zygote that divides by meiosis immediately after formation. From 

 this situation, diploid life cycles and cycles with alternation of gen- 

 erations seem to have evolved independently a number of times in 

 plants and animals. In the fungi, specialized mechanisms producing 

 recombination and diploidy have developed. The selective advan- 

 tage of diploidy and sexuality seems to lie in their provision for de- 

 velopmental buffering and the storage and release of variability, as 

 well as in the reduction of the amount of gamete and zygote wast- 

 age. Recombination may be modified in multicellular organisms by 

 mating systems leading to predominantly inbreeding or predomi- 

 nantly outbreeding individuals. 



REFERENCES 



The references are given at the end of Chap. 9. 



