Table 1.

Rates of Chromosomal Evolution and Hsa1 Fragmentation

Species	Haploid no.	CSUs relative to the placental ancestor^a	No. rearrangements relative to ancestral genome^b	Genomic rate^b	No. of Hsa1 fragments
dolphin	22	25	3	0.034	1
cat	20	27	6	0.068	2
human	23	29	6	0.068	1
macaque	21	28	7	0.080	1
mink	15	26	10	0.114	2
lemur	30	35	10	0.114	3
tree shrwe	31	35	10	0.114	2
horse	32	40	15	0.170	3
cow	30	41	16	0.182	3
bat	16	35	19	0.216	3
shrew	10	30	20	0.227	2
pig	19	41	22	0.250	6
gibbon	22	51	26	0.295	4
spider monkey	17	48	30	0.341	6
dog	39	64	39	0.443	7

↵a Y chromosome excluded in counts. Data are from O'Brien et al. (1999b), Wienberg et al. (2000), Murphy et al. (2001c), Yang et al. (2000)
↵b See Methods for description of calculation

The Origin of Human Chromosome 1 and Its Homologs in Placental Mammals