338 



The Journal of Heredity 



Yorkshire : these with seven longitudinal 

 red stripes on a white-roan field were 

 found in the clsss of dominant whites 

 (at birth), acquiring the stripes after 

 the weaning moult. At this time other 

 important genetic problems prevented 

 our testing the possibility of fixing the 

 unique i^atteni. Its make-up was from 

 the black birth-stripes of the wild 

 scrofa, which arc obliterated at moult, 

 with a weak dominance of Yorkshire- 

 white as the other factor: and a pecu- 

 liarity was the fact that, unlike their 

 prototype, the dark stripes became 

 darker, the white-roan field whiter, as 

 animal progressed in age. 



We may safely predict that any form 

 or design of color or pattern, be it belt, 

 stripes, white feet, or spots in any 

 particular locality, may be fixed to 

 reasonable heredity dependent on 

 homozygous pairs of chromosomes, 

 regardless of the number of factors in- 

 volved, so they fall inside of the species 

 number of chromosome pairs. But no 

 jjattcrn or design can be regularly per- 

 petuated where the factors are split in 

 the pair, i. e., when depending on any 

 heterozygous pair of chromosomes. 



THE USE OF MENDELISM. 



Recapitulating we say: — The Fancier 

 and the Mendelist may synthesize color 

 and pattern to their likings. Starting 

 with dominant white found on some 

 individual, family, or race, among 

 mammals or fowls, he may borrow from 

 another of the species the dye, from yet 

 another the stencil, and create unique 

 marking. Then with simple Mendelian 

 analysis will he prove, as with chemistry, 

 the possibility of fixing to heritable 

 [)cr])etuity his hand-made design. When 

 the ])articular type has been trued and 

 standardized by selective elimination ; 

 hom(jzygotized in each pair of chromo- 

 somes constructing it; and the race 

 from which each pair of these was taken is 

 known, then will he possess a delicate 

 "C. P. reagent" for finding the most 

 minute contamination in a suspect be- 

 longing to breeds with which he is 

 familiar. 



The fancier's Blue Andalusian is the 

 hybrid of black and white; the sjjotted 

 horse and the roan shorthorn are the 

 hybrid dominants of white and color 

 factors belonging to the same zygotic 



pair, always paramour in the sex cells 

 and somatic cells: and such can never 

 be fixed by breeder's selection : but they 

 may be created de novo in 100% when 

 an animal with one of these factors 

 doubled is mated with another with the 

 other factor doubled; so that at the 

 halving of the chromosome pairs in egg 

 and sperm to create the new life, this 

 receives the paramour that creates the 

 pattern. 



Conceiving that areas of color mark- 

 ings are modified by the time of differen- 

 tiation in the blastomcre or embryo 

 we then have a pleasing hypothesis for 

 the fact known by feather-fanciers and 

 pattern-breeders that the stable, 

 standard pattern is upset when to a line 

 of long inbred f ow4 or mammals an out- 

 cross of pattern of the same appearance 

 is introduced. In my own experience 

 and gleanings I find usually that the Fl 

 individuals of the outcross are usually 

 unchanged; the F2 and later generation 

 show the bad breaking-up of color pro- 

 portion and equilibrium. From this 

 may we surmise that the nicely balanced 

 barring on a "Felch" strain of Barred 

 Rocks depends on exactly so many days 

 and hours between the minimum body 

 temperature and blood pressure, pro- 

 ducing the white, and the same time 

 period of maximum temperature and 

 pressure producing the black, staining 

 the colorless gell that is constantly pass- 

 ing out of the follicle. Then if there is 

 introduced an out-cross of the "Barnes 

 Strain" having a difference of conges- 

 tive period , we would get the ' ' breaking- 

 up ' ' of the correct barring by interposi- 

 tion of black on white. 



Breeders of the now i)o])ular belted 

 hog, the Hampshire, have not attended 

 to the effect of outcrossing on their 

 families, so that when they add new 

 animals, the breeder of these has been 

 accused of sending hybrids. May we 

 moralize that the new dose must be 

 cautiously tested before general use. 



Let me add: that Mendelism, the 

 result of chromosome shuflling and scg- 

 gregation at the sexual i)reparation of 

 egg and s])enn, is the breeder's frac- 

 tirnating column and analytical balance: 

 it enables him to separate and weigh the 

 determining entities that make visible 

 the tyi)es, and then to resynthcsize 

 these to his uses and his fancies. 



