Aphids are insects with a sex determination model based on the presence of two X chromosomes (XX) in females and a single X chromosome (XO) in males.

Chromosome Pattern of the Patient, Showing an XO Cell (45 Chromosomes) from the Same Culture as the Cell in Figure 3. Of the 217 leukocytes analyzed, 42 (19.4 per cent) had 45 chromosomes, and 170 ...

One of the two sex chromosomes in animals that are determined by the XX-XY system; the only sex chromosome in animals whose sex is determined by the XX-XO system.

Bean et al. 2 asked if these modifications might predict differences between the maternal and paternal X chromosome in XX zygotes produced by mating XO males with XX individuals. They assayed ...