Explanation

XX and XO chromosome. XY and XY type sex determination seen in many insect and mammals including humans. Males have X and Y chromosome along with autosome and females have pair of ‘X’ chromosome along with autosome Parents Phenotypes Male Female Genotypes 44A + XY 44A + XX Gametes 22A + X 22A+Y 22A + A22A + X 22A+ X 22A+X Children 22A + X 44A + XX 44 A + XY Female 22A + Y 44 A + XY 44 A + XY Male Sex ratio Female : Male = 1 : 1 In plants The flowering plants are mostly bisexual and lack sex chromosomes. The unisexual flowering plants tent to have XX-XY type of sex chromosomal mechanism for sex determination. The female plants are XX and male plants are XY. XX and XO Type of Sex Determination Found in insect like grasshopper, cockroaches and bugs. Males have only X sex-chromosome and autosomes, female have pair of X-chromosome and autosome Parents Phenotypes Male Female Genotypes $AA + XO$ $AA + XX$ Gametes $A + X,\ A + O\ \ \ A + X,\ A + Y$ $\mathbf{F}_{\mathbf{1}}$-generation [image:5d_image34.emf] XX-XO type of sex determination