100
F R E D H. W I L T
phoretic techniques he separated two Hb types in both embryos (the
earliest examined was 5 days) and adults (which had a third minor Hb
component absent in the embryo). The two types of Hb seemed the
same in embryos and adults, although their relative proportions differed
markedly at different stages of development (cf. Simons, 1965). Wilt
(1962) found two components in the early embryo by use of electrophoretic techniques, and the two types were indistinguishable from the
two types to be found in the adult. Using antibody against the adult Hb,
agar-gel diffusion reactions obtained from extracts of embryos were
identical to the adult reactions after the embryo had attained about
9 somites. In extracts from the unincubated stage to the 9-somite stage,
cross-reacting material was found which was postulated to be a distinct,
transient, embryonic globin (Fig. 3). Manwell et al. (1963) introduced
FIG. 3. Diagrammatic summary of the precipitation lines formed in an agar-gel
diffusion analysis of embryonic hemoglobin antigens. The original details may be
found in the paper of Wilt (1962). The center well contains antihemoglobin γglobulin. The peripheral wells contain hemoglobin (from the adult) or extracts of
pooled blastoderms obtained from eggs incubated for the number of hours indicated
on each well.
the high resolution vertical starch-gel technique to this problem, and
they showed the presence in 5-day embryos of two distinct embryonic
Hb types, both of which were different from the adult types. The "fingerprint" of 5-day Hb was quite different from that of adult Hb. Deuchar
and Dryland (1964) have also shown two Hb types are present in 48-hr
embryos after having been cultured, in vitro, for 20 hr. Hell (1966)
examined 60-hr embryos by polyacrylamide-gel electrophoresis and found
2 bands (occasionally a third minor component), both of which migrated
differently from the adult components. The use of these high resolution
electrophoretic techniques leaves little doubt that the embryo prior to
4 or 5 days of incubation contains at least 2 types of Hb, and that these
are different from the adult components. Hashimoto and Wilt (1966)
have recently confirmed this and analyzed the molecular basis of the
heterogeneity of 5-day Hb by the same techniques they applied to adult
Hb. Three easily distinguishable components are found in hemolysates
F R E D H. W I L T
phoretic techniques he separated two Hb types in both embryos (the
earliest examined was 5 days) and adults (which had a third minor Hb
component absent in the embryo). The two types of Hb seemed the
same in embryos and adults, although their relative proportions differed
markedly at different stages of development (cf. Simons, 1965). Wilt
(1962) found two components in the early embryo by use of electrophoretic techniques, and the two types were indistinguishable from the
two types to be found in the adult. Using antibody against the adult Hb,
agar-gel diffusion reactions obtained from extracts of embryos were
identical to the adult reactions after the embryo had attained about
9 somites. In extracts from the unincubated stage to the 9-somite stage,
cross-reacting material was found which was postulated to be a distinct,
transient, embryonic globin (Fig. 3). Manwell et al. (1963) introduced
FIG. 3. Diagrammatic summary of the precipitation lines formed in an agar-gel
diffusion analysis of embryonic hemoglobin antigens. The original details may be
found in the paper of Wilt (1962). The center well contains antihemoglobin γglobulin. The peripheral wells contain hemoglobin (from the adult) or extracts of
pooled blastoderms obtained from eggs incubated for the number of hours indicated
on each well.
the high resolution vertical starch-gel technique to this problem, and
they showed the presence in 5-day embryos of two distinct embryonic
Hb types, both of which were different from the adult types. The "fingerprint" of 5-day Hb was quite different from that of adult Hb. Deuchar
and Dryland (1964) have also shown two Hb types are present in 48-hr
embryos after having been cultured, in vitro, for 20 hr. Hell (1966)
examined 60-hr embryos by polyacrylamide-gel electrophoresis and found
2 bands (occasionally a third minor component), both of which migrated
differently from the adult components. The use of these high resolution
electrophoretic techniques leaves little doubt that the embryo prior to
4 or 5 days of incubation contains at least 2 types of Hb, and that these
are different from the adult components. Hashimoto and Wilt (1966)
have recently confirmed this and analyzed the molecular basis of the
heterogeneity of 5-day Hb by the same techniques they applied to adult
Hb. Three easily distinguishable components are found in hemolysates