Table 1. Genome-wide distribution of genes used in the phylogenetic study.

Chromosome arm	Length (Mb)	Number of genes	Genes per 5 Mb
X	24.4	3	0.6
2R	61.5	19	1.5
2L	49.4	13	1.3
3R	53.2	8	0.8
3L	42.0	6	0.7
Total	230.5	49	1.0