Biology Reference
In-Depth Information
Fig. 58.
Schematic representation of the production of a maternal zygotic (MZ
hdf/fgfr1
)
mutant
by germ-line replacement. At the midblastula stage, the donor cells are transplanted from the
deep layer of the blastoderm into the animal-pole region of a hybrid host embryo at the same
stage. Successful PGC transfers are scored at segmentation stages from 1 to 4 dpf. The host
embryos with
fgfr1
-/- PGCs were mated with
fgfr1
+/- males to obtain MZ
fgfr1
-/- embryos
(from Shimada and Takeda, 2008, modifi ed)
resulting in both polar body retension and suppression of dorso-ventral
differentiation (Yamaha et al., 2002).
Influence of maternal genes seems to last even beyond the early
embryonic development. For example, from a construction of a maternal EST
library containing 2,431 sequences, Mommens et al. (2010) have identifi ed
two genes
HCOO353
and
HHCO1517
that are positively correlated with the
hatching process and the third one
HHCOO255,
that is negatively correlated
with the percentage of normal blastomeres. Apparently, these maternal
genes determine the quality of eggs. Incidentally, the non-symmetrically
cleaving eggs used as a predictor of egg quality in
Limanda ferruginea
(Avery
and Brown, 2005) and
Gadus morhua
(Hansen and Puvanendran, 2010) may
represent mutants of maternal genes that determine egg quality.
