The genetic and the operative evidence relating to secondary sexual charactersMorgan, Thomas Hunt
Science
The genetic and the operative evidence relating to secondary sexual characters
Morgan, Thomas Hunt
Genetics; Poultry; Sex (Biology)
| +-------------+-------------+----------------+-------------+-------------+ |
| | | | | | | |
|Silver Males Silver Males GOLD MALES Gold Males Silver Females Gold Female. |
|(Eng. type) (Belgian type) (ENG. TYPE 1912) (Belgian type) |
| ============== |
| ============== |
+----------------------------------------------------------------------------------------+
| |
|_F_ |
| |
| SILVER MALE (offspring of C) X SILVER FEMALE (pure) |
| | |
| +------------------------------------+------------------------+ |
| | | | |
|Silver Males (English type) Silver Females Gold Females |
+----------------------------------------------------------------------------------------+
Smith and Haig have reported the following curious case of
hen-feathering. Smith had a breed of White Leghorns with cocks of two
classes--those that assumed cock plumage at 6 months and those that are
like the hens for 8 months, after which they slowly assumed the
cock-feathering. The difference is hereditary and appears to segregate.
Possibly this breed had one factor at least for hen-feathering that is
effective for young birds, but not for older ones, or some of the birds
pass through a stage when they produce an internal secretion that
disappears later. But it is also possible, and perhaps more probable,
that the young birds, not cock-feathered, have remained longer in the
juvenile stage than the others, so that they might be said to be falsely
hen-feathered.
Public-domain text, read in full here on John Shaqi.
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