...-mail: dhkuo@mail.utexas.edu ) 1 10 2003 © 2004. 2004 Cell lineage Cell interaction Rostral segment Leech Helobdella robusta In segmented animals, segments are characterized as repeating morphological units aligned along the anteroposterior axis that share the same...

..., the glossiphoniid leech, Helobdella robusta ,and examined its expression by reverse transcription polymerase chain reaction(RT-PCR) and whole-mount in situ hybridization. The peak of Hro-hh expression occurs during organogenesis (stages 10-11). No patterned expression was detected within the segmented portion...