Temporal cell fate transitions in mushroom body neurons seem significantly delayed in Dp(2;1)JS13 animals. For example, at 3.75 days after larval hatching when wild-type animals are mostly producing α'/β' neurons, the majority (77%) of MB neurons born in Dp(2;1)JS13 females still develop into γ neurons. Furthermore, not until 4.25 days after larval hatching has the production of γ neurons in the Dp(2;1)JS13 dropped to a percentage (15%) comparable to the control's (20%) at 3.75 days after larval hatching. In addition, α'/β' neurons consist of 12% versus 7% of the mushroom body neurons born within 6hrs before pupal formation in Dp(2;1)JS13 mutants versus controls, suggesting a slight delay in the Dp(2;1)JS13 α'/β' to pioneer α/β transition as well. Approximately 45 pioneer α/β neurons are present in Dp(2;1)JS13/+ adult flies, compared to an average of 60 in wild-type.