Inheritance of Characteristics in Domestic Fowl

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

Davenport, Charles Benedict

Heredity; Poultry

× Span.| 6-5 |  3 | .. | .. | .. |  2 | .. | .. | .. | .. | .. | .. | .. |
    |  20  |709|1963|    Do.      | 4-4 |1578|    Do.      | 6-5 | 12 |  5 | .. |  1 | 15 |  1 | .. | .. |  1 | .. | .. |  1 |
    |  21  |821|7413|Silk. × Coch.| 5-5 |6095|Silk. × Coch.| 5-5 |  1 | .. | .. |  1 |  7 | .. | .. | .. |  2 | .. | .. | .. |
    |  22  |821|7423|    Do.      | 5-5 |6095|    Do.      | 5-5 |  3 | .. | .. | .. |  7 | .. | .. | .. | .. |  1 | .. |  1 |
    |  23  |821|7428|    Do.      | 5-5 |6095|    Do.      | 5-5 |  5 | .. |  1 |  4 | 13 | .. | .. |  2 | .. | .. | .. |  1 |
    |  24  |821|7408|    Do.      | 5-5 |6095|    Do.      | 5-5 |  3 |  1 | .. | .. |  8 | .. | .. | .. |  1 |  1 | .. | .. |
    |      |   |    |                                            +----+----+----+----+----+----+----+----+----+----+----+----+
    |      |   |    |       Total (208)                          | 64 |  8 |  2 |  7 |102 |  2 |  1 |  3 |  8 |  2 |  1 |  8 |
    +------+---+----+--------------------------------------------+----+----+----+----+----+----+----+----+----+----+----+----+
    [A]: Includes 1 case of 3-4 toes.


Comparing tables 10 and 11, it is at once clear that in the second
hybrid generation the proportion of extra-toed offspring has
decreased. This accords with expectation, if extra-toe is dominant,
for then only 75 per cent would be of the dominant type in F2, while
100 per cent would be of that type in F1.

Table 12 will enable us to analyze the difference of the proportions
in tables 10 and 11.


    TABLE 12.--_Percentages of the various types of toes in F1 and F2
    of the polydactyl hybrids compared._

    +------+---------------+------------------+------------------+
    |      |    _a_.       |       _b_.       |       _c_.       |
    |      |Houdan hybrids.|Silkie hybrids (as|Silkie hybrids (as|
    |No. of|               |    observed).    |  interpreted).[A]|
    |toes. +---------------+------------------+------------------+
    |      |   F1. |  F2.  |   F1. |   F2.    |   F1. |    F2.   |
    +------+-------+-------+-------+----------+-------+----------+
    | 4-4  |  27.3 |  47.4 |  9.4  |  31.7    |  4.3  |  30.8    |
    | 4-5  |  19.1 |  12.1 |  9.4  |   7.7    |  2.9  |   3.8    |
    | 4-6  |  .... |    .3 | ....  |   1.0    |  1.5  |   1.0    |
    | 5-5  |  53.6 |  39.7 | 81.2  |  51.4    | 76.8  |  53.4    |
    | 5-6  |  .... |    .5 | ....  |   4.3    |  5.8  |   5.8    |
    | 6-6  |  .... |  .... | ....  |   3.9    |  8.7  |   5.3    |
    +------+-------+-------+-------+----------+-------+----------+
    [A] Reduced duplex and triplex toes classified as typical duplex
    and triplex.

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

Inheritance of Characteristics in Domestic Fowl

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