212 CHAPTER IS 



■ inbred lines img sold inexpensively. Hel 



practical importance; a fuller understanding 

 single cross fu brids arc then this phenomenon requii 



other Since I rous the biochemical, molecular I c % c I . 



rbrid plant, seeds produced b) - . and w 



touble Ct plentiful .\n<.\ can be 



SUMMARY AND CONCLUSIONS 



I he whose functi produce the I 



popi* pool The gene pool and the l 



•n> will remain forever unchanged if: the population 

 rtk drift does not occur, mutation does not - 

 direction preferentially . no differential selection is made I 



•IK |iist like the • lr however. conditions is not 



Bed. a shift in the composition of the gene pool will occur, in other words, 

 frequencies will change and so will the frequencies of different genotvpes until a new 

 equilibrium is attained. 



It 't onlv species formation hut all oH hiological evolution is b 



upon changes in the gene pool 



I he roles th..r mutation and selection have in establishk mc equilibrium is 



discussed tor those rare mutants which lower reprodlK 

 lethal, dominant detriment.il. recessive lethal, or l lemmental 



lorn breeding resulting the 



freq' I he per generation rate oi reduction in betel 



due to inbreeding is ' : tor self-fertilization, '» for sib • »r half-sib 



and ¥u for cousin matings. H<" Lilizing individuals leads 



i h\ heterosis, or h\bnd '• 



Hel • i phenotvpic result ol in because the heiero- 



idaptive! ft to one or to both types o\ homo' peal tm 



nee economically. 



REFERENCES 



\lli». klc Cells and Evolution." Scical tin >5:87 M 



If. polls H' 



and the Origin of Sp )rd EdL, New Yofi Cob 



; ' 

 Doha netics and M in WHej 



Gowcn, I. W. (Ed), A wa: low . S 



Mixed Populatioi • 



Reprinted a < Peters, J. A. (Ed.). Eng -wood 



, s i Pi H trimenta in 8 



,,! m i od ( tiffs N I Prentice-Hall, 



■ •.v-Hiil. 



