P{lacW} in mei-P19P19 maps 79bp from the P{PZ} insertion in mei-P1903477.
Mutant for female meiotic segregation: 0% X chromosome exceptions from X/X females. 1.2% 4th chromosome exceptions from X/X females. 16.7% X chromosome exceptions from X/Bal females. 6.7% 4th chromosome exceptions from X/Bal females. Axs-like mutant. Primarily affects achiasmate chromosome segregation. Only the segregation of achiasmate chromosomes is affected. Rate of X chromosome nondisjunction is two to three fold higher than that of 4th chromosome nondisjunction. X and 4th chromosome nondisjunction show a strong positive correlation. The majority of simultaneous X and 4th chromosome nondisjunction is non-homologous XX - 44 segregation. Exchange is normal.