THE ANALYSIS OF TETRAD DATA
Haig P. Papazian · Genetics · 1952
HE theory of four-strand crossing over was founded by JANSSENS T (1909).H e arrived at his theory in an attempt to explain tetrads in which all four cells are different.None such had been observed at that time but JANSSENS believed, by a happy metaphysical insight, that since germ cells were always produced in groups of four, the four must be aH qfferent.It is curious that when tetrads were isolated and four-type tetrads obtained, their significance was often missed.A useful summary of the types of tetrad produced #by various crossovers has been given by WHITEHOUSE (1942, 1949).