02642cam a22003613u 4500 57460 UtSlPG 20260610134326.0 m cr n 260607r2018||||utu|||||o|||||||||||||| d 19014430 UtSlPG en iso639-1 QH Morgan, Thomas Hunt, 1866-1945 The genetic and the operative evidence relating to secondary sexual characters Salt Lake City, UT : Project Gutenberg, 2018 1 online resource : multiple file formats text txt rdacontent computer c rdamedia online resource cr rdacarrier Carnegie Institution of Washington publication no. 285 Release date is 2018-07-07 Produced by Larry B. Harrison, Bryan Ness, Chuck Greif and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) "The Genetic and the Operative Evidence Relating to Secondary Sexual Characters" by T.H. Morgan is a scientific publication written in the early 20th century. This work delves into the genetic and physiological aspects of secondary sexual characteristics in birds, particularly focusing on the Sebright bantam and other fowl as subjects for analysis. It covers various experiments and findings related to plumage differences between hen-feathered and cock-feathered males, exploring how these traits are influenced by factors such as heredity and endocrine signaling. The opening of the book sets the stage for an in-depth study of the genetic mechanisms at play in determining secondary sexual characteristics. It begins with a discussion of the existence of two male types within certain poultry breeds and introduces the author's experimentation with castrating hen-feathered Sebrights to observe changes in plumage. Morgan recounts his observations regarding the physical alterations in feathering post-operation, revealing insights into the relationship between the gonads and plumage expression. This portion establishes not only the methodology and initial findings but also hints at the broader implications for understanding sexual differentiation in birds. (This is an automatically generated summary.) Original publication data not identified Poultry Sex (Biology) Genetics Carnegie Institution of Washington publication no. 285 https://www.gutenberg.org/ebooks/57460 98291 98291