Heredity and sex . Fig. 41. — Reciprocal cross of Fig. 40. Upper line, black cock andbarred hen. Second line, ¥i, barred cock and black hen. Third line, F-i,barred hen and cock, black cock and hen. (Cuts from Rehable PoultryJournal.) 72 HEREDITY AND SEX We lack here the certain evidence from cytology thatwe have in the case of the insects. Indeed, there issome cytological evidence to show that the male birdis heterozygous for the sex chromosome. But theevidence does not seem to me well established; whilethe experimental evidence is definite and has beenindependently obtained by Bateson, Pearl,
Heredity and sex . Fig. 41. — Reciprocal cross of Fig. 40. Upper line, black cock andbarred hen. Second line, ¥i, barred cock and black hen. Third line, F-i,barred hen and cock, black cock and hen. (Cuts from Rehable PoultryJournal.) 72 HEREDITY AND SEX We lack here the certain evidence from cytology thatwe have in the case of the insects. Indeed, there issome cytological evidence to show that the male birdis heterozygous for the sex chromosome. But theevidence does not seem to me well established; whilethe experimental evidence is definite and has beenindependently obtained by Bateson, Pearl, Sturtevant,Davenport, Goodale and myself. However this may be,the results show very clearly that here also sex is con-nected with an internal mechanism that is concernedwith other characters also. This is the mechanism ofMendelian heredity. Whether the chromosomes sufficeor do not suffice to explain Mendelian heredity, thefact remains that sex follows the same route taken bycharacters that are recognized as Men
Size: 1392px × 1794px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1910, booksubjectsex, bookyear1913
