Morgan, Thomas Hunt, Experimental zoölogy

(New York : London :  The Macmillan Company ; Macmillan & Co., Ltd.,  1907.)

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ii6                       Experimental Zo'dlogy

of the other colors. The piebald character stands as a unit con¬
trasted with uniform coat, but is independent of any particular
color.

Data for Other Mammals and Man

A few other cases in mammals, that seem to show discontinu¬
ous inheritance, are known. Castle and Davenport have both
called attention to cases of so-called wonder-horses, i.e. horses
with remarkably long mane and tail. In the case of "Linus I"
the mane was i8 feet long and the tail 21 feet. The parents
and grandparents of these horses also had unusually long hair,
which increased in successive generations. The data are insuffi¬
cient to show the relation of dominance and recessiveness in this
case, but the persistence of the long hair seems to indicate its
dominance.^

Harper and Hurst have recently examined certain data in
regard to the inheritance of coat color in horses. Harper deals
with the problem from the standpoint of prepotency of certain
colors in regard to ancestry, selection, age, and sex. Hurst shows
that bay and brown colors dominate completely chestnut, and
there are definite indications that these two colors follow Mendel's
law.

Some statistics recently published (1904) by A. G. Bell have
furnished Davenport with material to study the relation of black
color to white color in sheep. The data show that when three
white individuals having as far as known white ancestors were
crossed with black sheep, the 13 lambs resulting {F-^ were white,
showing the dominance of white. Of 20 offspring from black
parents all were black.^ When a black (recessive) individual
was mated with a dominant white (one of whose parents was
white and one black), 26 lambs were white and 25 black, which
is the Mendelian expectation. When a dominant-recessive
white was mated to a dominant-recessive white, 40 were white
and 7 were black.    The expectation is 25 per cent black.    The

■■ In guinea pigs the long hair is recessive.

^ One uncertain case of white is given that is not above suspicion.
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