Detection of Normal and Aberrant Chromosomes in Chicken Embryos and in Tumor Cells

INTRODUCTION Avian cells, including those of Gallus domesticus, contain numerous chromosomes. Most of these are very small and, therefore, difficult to characterize on strictly morphological grounds. Cytologists conducting studies from 1906 to 1957 reported diploid chromosome numbers from 12 to 80 for the chicken (Brant, 1952; Loyez, 1906; Yamashina, 1944). Given the difficulties of bird karyology and inadequate techniques, the field of avian cytogenetics was slow to develop. Fundamental genetic questions easily answered for species such as Drosophila melanogaster (fruit fly) remained unanswered for birds, including the chicken. It is only within the last 15 or so years that significant breakthroughs have been made (Abbott and Yee, 1976; Bloom, 1978, 1979a,b). What are these basic genetic questions and why are they important in poultry genetics and breeding? In his historic work of 1949, Genetics of the Fowl, Professor F. B. Hutt discussed the importance and potential contribution to poultry genetics . . .