Section 14 — Animal genetics and breeding 



tiveness of various selection methods and the 

 importance of genotype by environment interac- 

 tions under two levels of nutrition. The principal 

 difference between the levels consisted of 10 

 per cent dried brewers yeast in the Good ration 

 while the Poor ration contained no yeast. All 

 populations were raised under the conditions 

 of 33 °C and 70 per cent R.H. In addition to an 

 unselected control, there were eight experimental 

 populations as follows: GL = selected large 

 on performance under the good level each gen- 

 eration, PL = selected large on performance 

 under poor [level each generation, gpl = selec- 

 ted large on average performance under both 

 levels, gpl = selected large under good or 

 poor levels in alternating generations, and simi- 

 lar four populations for small direction. Each 

 population was represented each generation by 

 40 single pair matings. Sets of full sibs from each 

 mating were reared on both good and poor 

 rations. In addition, each mating was placed in 

 standard wheat medium for reproduction. Se- 

 lection was made on the basis of full sibs reared 

 either under good, poor or average of both levels, 

 depending on the selection methods. After 

 choosing the best eight families in each popula- 

 tion, five males and five females for each selected 

 family were taken from the sib groups raised 

 in the standard medium. They were mated at 

 random with the restriction that full-sib mating 

 was avoided. 



As selection proceeded, the behavior of popu- 

 lations under two environments showed striking 

 interactions. The gains per generation in GL 

 populations under good and poor levels were 

 65 |ag (direct response) and 60 ug (correlated 

 response), respectively, and corresponding values 

 in PL were 55 ug (correlated response) and 98 ug 

 (direct response). GPL and gpl were inter- 

 mediate between GL and PL or a little more 

 similar to those of PL. In other words, regres- 

 sions of population means on generation under 

 two environments are nearly parallel for GL but 

 not in PL, where the absolute difference observ- 

 ed in early generations lessened or disappeared 

 in later generations. On the other hand, selec- 

 tion for small gave a completely reverse picture. 

 Regressions (gain per generation) for PS under 

 the two environments were alike (87 ug vs. 

 73 ug) but were greatly different in GS (106 ug 

 vs. 53 ug). An interesting response developed in 

 one of the GS populations. Its average weight 

 under the poor environment was consistently 

 heavier than under good for the last 4 genera- 

 tions. Asymmetrical selection responses observ- 

 ed were entirely dependent on the environment, 

 i.e. larger response toward small under good but 

 reverse under poor level. Realized heritability 



seems to be higher for small direction than for 

 large, although differences between environments 

 were not appreciable. 



Supported by Grant G- 15824, National 

 Science Foundation. 



14.22. Transfer to Descendency of Alterations In- 

 duced in the White Leghorn by Repeated 

 Injections of Heterologous Blood. J. Stroun, 

 L. Stroun-Guttieres, J. Rossi and M. 

 Stroun (Geneva, Switzerland). 



The authors have repeatedly injected blood by 

 the intra-peritoneal route from the grey guinea 

 fowl to successive generations of cocks and hens 

 descending from a white Leghorn strain with 

 stable characteristics. Concurrently with this 

 test Leghorn group, they raised a check Leghorn 

 group treated under identical conditions with 

 blood from white Leghorn, and also a control 

 Leghorn group left untreated. In each new genera- 

 tion obtained through artificial insemination, 

 fowls remaining up to the standards of the white 

 Leghorn are selected from both treated groups 

 and submitted to the blood injections. More- 

 over, from among the F4 birds in the control 

 group, the authors set up three new Leghorn 

 groups treated under identical conditions with 

 blood from Austhralorp, Rhode Island Red and 

 white Leghorn respectively. 



Results from Fo to F6 (February 1963): No 

 alterations are noticed in either check or control 

 Leghorn groups. In the test group, however, 

 which was submitted to injections of blood from 

 grey guinea fowl, there are in each generation 

 from F2 onward a few animals with alterations 

 in the colour and quality of their feathers and in 

 the pigmentation of their feet. Such alterations 

 do not appear in the blood treated Leghorn 

 fowls, but in birds of the following generation, 

 independently of any injection whatsoever. They 

 are maintained in the descendency which is no 

 longer treated and are transmitted both by the 

 mother and the father birds. In the groups treat- 

 ed with blood from Austhralorp and Rhode 

 Island Red, alterations begin to appear as from 

 F 2 . 



C.R. Acad. Sciences 255, 781-783, 1030-1032, 

 1962. 

 Biol. Med. 1963, to be published. 

 Arch. Sc, Geneve, 1963, to be published. 



257 



