Inheritance of Characteristics in Domestic Fowl

Name: Inheritance of Characteristics in Domestic Fowl
Author: Davenport, Charles Benedict

Davenport, Charles Benedict

Heredity; Poultry

+-------+---------------+---------+
    | Type. |    Zygotic    |  Soma.  |
    |       | constitution. |         |
    +-------+---------------+---------+
    | _a_   | M2L2[A]       |   Y     |
    +-------+---------------+---------+
    | _b_   | M2Ll          |   Y     |
    +-------+---------------+---------+
    | _c_   | MmL2          |   Y     |
    +-------+---------------+---------+
    | _d_   | MmLl          |   Y     |
    +-------+---------------+---------+
    | _e_   | M2Ll          |   Y     |
    +-------+---------------+---------+
    | _f_   | M2l2          |   I     |
    +-------+---------------+---------+
    | _g_   | MmLl          |   Y     |
    +-------+---------------+---------+
    | _h_   | Mml2          |   I     |
    +-------+---------------+---------+
    | _i_   | mLML          |   Y     |
    +-------+---------------+---------+
    | _k_   | mLMl          |   Y     |
    +-------+---------------+---------+
    | _l_   | m2L2          |  oo     |
    +-------+---------------+---------+
    | _m_   | m2Ll          |  oo     |
    +-------+---------------+---------+
    | _n_   | mlML          |   Y     |
    +-------+---------------+---------+
    | _o_   | mlMl          |   I     |
    +-------+---------------+---------+
    | _p_   | m2Ll          |  oo     |
    +-------+---------------+---------+
    | _q_   | m2l2          | Absent  |
    +-------+---------------+---------+
    [A] This convenient form of zygotic formulæ, using a
    subscript 2 instead of doubling the letter, is proposed
    by Prof. W. E. Castle.


It is a consequence of this second hypothesis that, in F2, of every
16 young 9 should have the Y comb; 3 the I comb; 3 the oo comb,
and 1 no comb at all. It follows further that the progeny of two F2
parents will differ in different families. Thus if a Y-combed bird
of type _a_ be mated with a bird of any type, _all_ of the progeny
will have the Y comb.

From Y-combed parents of various types taken at random 4 kinds of
families will arise having the following percentage distribution of
the different types of comb:

    1. Y comb, 100 per cent.
    2. Y comb, 75 per cent; I comb, 25 per cent.
    3. Y comb, 75 per cent; oo comb, 25 per cent.
    4. Y comb, 56.25 per cent; I comb, 18.75 per cent; oo comb,
         18.75 per cent; absent, 6.25 per cent.

Again, mating two extracted I combs of F2 should yield, in F3, two
types of families in equal frequency as follows:

    1. I comb, 100 per cent.
    2. I comb, 75 per cent; no comb, 25 per cent.

Again, mating two extracted oo combs of F2 should yield, in F3, two
types of families in equal frequency, as follows:

    1. oo comb, 100 per cent.
    2. oo comb, 75 per cent; no comb, 25 per cent.

Single comb × Y comb should give families of the types:

Public-domain text, read in full here on John Shaqi.

Inheritance of Characteristics in Domestic Fowl

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