LIVE-STOCK GENETICS 



Review of the Work in Experimental Animal Breeding, Now Under Way at the 

 Various Agricultural Experiment Stations in the United States. 



The Research Committee on Animal Breeding 



BREEDING domesticated ani- 

 mals for research in genetics 

 is restricted by the great expense 

 it involves, the long generations, 

 and the small number of individuals pro- 

 duced at a generation, not to mention 

 other difficulties. Genetists have there- 

 fore used plants for experiment, wher- 

 ever it appeared that a problem could 

 be solved equally well in either medium. 

 Furthermore, a good many lines of 

 experimental animal breeding do not 

 lend themselves to any immediate end 

 of economic importance. For these 

 reasons, the agricultural experiment 

 stations in the United States have gone 

 into this line of research only to a 

 limited extent, and some of the work 

 they have done is little known as com- 

 pared with the purely experimental and 

 more fully reported investigations made 

 at universities and other institutions. 



In order that the contribution which 

 the experiment stations are making to 

 genetics may be appreciated, the Re- 

 search Committee on Animal Breeding 

 of the American Genetic Association 

 presents the following report, reviewing 

 part of their work. No doubt it will be 

 found that some important lines of 

 investigation have been omitted; and to 

 save space the committee has ignored 

 many breeding projects, some of them 

 on a large scale, which have for their 

 purpose the improvement of a breed 

 by the same method used by farmers 

 and ranchmen, and which are likely to 

 throw little, if any, new light on the 

 laws of heredity. Experiments of this 

 nature often take up most of the atten- 

 tion of genetists who work with live-stock 

 at the experiment stations, and their 

 economic importance is very great, but 

 a review of them was thought to be of 

 little interest in this Journal. 



Probablv no station has made more 



contributions to the theory of animal 

 breeding than has that of Maine, whose 

 department of biology, organized in 

 1907, is directed by Raymond Pearl, 

 and whose staff includes 10 associates 

 and assistants and a number of graduate 

 students. To date 72 papers have 

 appeared from this laboratory, most of 

 them dealing with some phase of 

 genetics. Among the problems now 

 under investigation is the important 

 one of the inheritance of fecunditv in 

 poultry, to which some notable contri- 

 butions have already been made . ' ' Two 

 definite and clear-cut results have 

 already come to light. These are: 



"First: that the record of egg pro- 

 duction or fecundity of a hen is not of 

 itself a criterion of any value whatsoever 

 from which to predict the probable egg 

 production of her female progeny. An 

 analysis of the records of production of 

 large numbers of birds shows beyond 

 any possibility of doubt that, in general, 

 there is no correlation between the egg 

 production of individuals and either 

 their ancestors or their progeny. 



"Second: that, notwithstanding the 

 fact just mentioned, fecundity is, in 

 some manner or other, inherited in the 

 domestic fowl. This must clearly be so, 

 to mention but a single reason, because 

 it has been possible to isolate and 

 propagate from a mixed flock 'pedigree 

 lines' or strains of birds which breed 

 true, generation after generation, to 

 definite degrees of fecundity." 



This interesting conclusion was 

 reached after the failure of a long-con- 

 tinued experiment to increase the egg- 

 production of hens by simple "mass 

 selection." As to the real solution, 

 Pearl thinks the capacity for high egg 

 production is inherited through the sire 

 rather than the dam, experiments having 

 shown that high egg producing hens 



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