Recent contributions to the scientific substantiation of the gene theory of sexuality in Galinaceae

The genetic determinism of sex and the equal male to female ratio in chicken was explainedin literature by the existence of the male sex, homogametic ZZ, and of the female sex, heterogameticZW, as well as by the existence of genes in chromosome Z, however, with no corresponding genes of itin chromosome W. This paper presents experiments of genetic recombination which allows theidentification in generation F1 of the dominant sex gene linked to the gene that determines themonitored colour phenotype. In the same generation the recessive sex allele was identified inchromosome Z. In generation F2, males and females are in equal ratio in every category of genotypes.Three categories of feather colour genotypes were produced: dominant homozygous, heterozygousand recessive homozygous. The experimental results show the presence of two genes in chromosomeW, the dominant sex gene and the gene transmitting the colour of the feathers, contrary to thehemizygotic theory of Morgan.