Biology Reference
In-Depth Information
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. The results of Wong et al. (2010) confi rm that the OSCs drawn
from the ovary of 3-month old zebrafi sh still retain bisexual potency and
the germ cells supporting somatic cells of undifferentiated gonad in the
two week-old hybrid fry have also retained bisexual potency. For reasons
not known, the fertility is not recovered, when hybrid sterile fry are used
as recipients in male medaka progenies (Shimada and Takeda, 2008) but
in female danio progenies.
SSCs: The PGC-derived SSCs have also retained sexual plasticity. Okutsu
et al. (2007) intraperitoneally microinjected testicular cell suspension
containing 18,000 cells with 1,000, i.e., 56% labeled SSCs (as against 12%
labeled OSCs in Yoshizaki et al., 2010) drawn from the dominant orange
colored diploid rainbow trout into the alevins of triploid sterile masu
salmon. The resultant xenogenic trouts were both males and females, clearly
indicating that bisexual potency has been retained not only by the SSCs but
also the germ cells supporting somatic cells in the undifferentiated gonads
of the alevins. On maturation, 84% of the recipient males produced milt
and 50% of the sired F
1
progenies, which developed the fi nger print pattern
like that of their fathers. Similarly, 10% of the recipient females matured
and 90% of their eggs hatched.
In another series of experiments, Yoshizaki et al. (2011) transplanted
testicular cell suspension of the dominant orange colored diploid
rainbow trout into the alevins of triploid masu salmon. Two years after
the transplantation, the recipients showed nuptial body coloration and
males with extended jaws, both of which are typical secondary sexual
characteristics of salmonids. In yet another experimental series, Yoshizaki
et al. transplanted 500,000 cryopreserved and thawed testicular cells into
the alevins of 3n masu. At the second spawning season, 10 mature males
and fi ve females of masu salmon produced the donor-derived diploid
and aneuploid sperm. On the other hand, F
1
female progenies produced
functional eggs. Hence it is possible to generate functional eggs and sperm
using the cryopreserved SSCs of the trout, so long as the recipients are
alevins that have undifferentiated gonad with germ cells supporting somatic
cells still retaining bisexual potency.
In the early 90s, another Japanese group led by CA Strussmann
introduced the sperm cells into sterile testis of the pejerrey
Odontesthes
bonariensis
and found the sperm to have been alive until 10 week pt (see
also Pandian, 2003). Recently his group surgically transplanted the donor
spermatogonial cells, isolated from juvenile pejerrey into the sterile adult
Patagonian pejerrey
O. hatcheri,
which have been previously partially depleted
of endogenous gonial cells by a combination of treatment with busulfan
(40 mg/kg) at high water temperature (25ºC). The donor-derived SSCs
have colonized the recipient's gonad and resumed spermatogenesis
