Table 1.

Organization and conservation of the 13 ancestral chromosomes of pipanuran genomes

Phylogenetic position	Structural event
(1) Stem pipid lineage	J + K → JK
	D. + E. → D.E
	I• + •H → I • H (Rob. fusion)
(2) P. adspersus lineage after divergence from R. temporaria	A + M → A1.m1 + m2.A2
(3) E. pustulosus lineage after divergence from E. coqui	M + I → M.I (Rob)
	K + D → K.D (Possible end-end)
(4) E. coqui lineage after divergence from E. pustulosus	G1 • G2 → G1• + •G2 (Rob. fission)
	A1 • A2 → A1• + •A2 (Rob. fission)
	I + K → I • K (Rob. fusion + inversion)
	E + F1•F2 + B1•B2 + H → E•F1 + F2•B2 + B1•H
(5) H. boettgeri lineage after divergence from Xenopus	M + J•K → MJK
(6) X. laevis progenitor lineage after divergence from X. tropicalis	L + M → LM

Rob Robertsonian.

Middle-dots (i.e., “•”) represent centromeres. Periods (i.e., “.”) represent translocation breakpoints.