Embryos derived from females expressing hb^hb2 show partially restored abdominal patterning in comparison with hb^Δ. Between one and four abdominal segments are seen, compared to the eight seen in wild type.

hb protein is distributed throughout the posterior in a shallow gradient that is lowest at the posterior pole: larvae fail to develop abdominal segments. hb protein expression is repressed in the pole cells. The hb protein level is lowered sufficiently to see weak posterior expression of kni and develop a patch of abdominal hairs posteriorly. If the female from which the embryos were derived contained an extra wild type copy of nos the larvae would have two or three abdominal segments.