Differentiation in Hermaphrodites - Genetic Sex Differentiation in Fish - page 117

that is highly expressed in developing male gonad (see Gardner et
al., 2003).
(ii) Dmrt : Table 27 shows that Dmrt1 expression pattern is intimately
linked to male gonadogenesis and further differentiation in both
protogynous and protandrous hermaphroditic fi shes. In M. albus
too its expression is stronger in the testis than in the ovotestis and
ovary. Dmrt1 is not only differentially expressed and up-regulated in
gonads of different phases in female to male sex change, but also it is
restricted to specifi c phases and specifi c cells of spermatocytes stage

Table 27. Summary of Dmrt1 gene complex in downstream sex differentiation in sequential
hermaphroditic fi shes

Species/Reference Gonadal

expression

Expression levels Expression location

Protogynous hermaphrodites

Monopterus albus
Huang et al. (2005)

Testis, Ovotestis
ovary

High in testis Differentiating testis

Epinephelus coioides
Wang et al. (2004)

Testis Higher in testis -

E. coioides
Xia et al. (2007)

Testis - Spermatogonia,

Spermatocytes

Halichoeres tenuispinis
Jeong et al. (2009)

Testis - -

Protandrous hermaphrodites

Acanthopagrus schlegeli
He et al. (2003)

Testis Higher in mature

testis

-

Sparus auratus
Liarte et al. (2007)

Testis Decrease during

sex change

-

I and II; however, it is not expressed in the supporting Sertoli cells.
At the initial phase of sex reversing E. coioides, no Dmrt1 protein is
detected; with continued MT-feeding and consequent sex reversing,
Dmrt1 begins to express and expression progressively increases
during the course of 5 weeks of MT-feeding. Signifi cantly, the protein
has been detected only in spermatogonia and spermatocytes of the
sex reversed male but not in its spermatids, an expression profi le
very much similar to that in zebrafi sh (Guo et al., 2005).

Both phylogenetic analysis and substitution estimates have revealed
that EcDmrt1 is related to that of the protandrous A. schlegeli (He et
al., 2003) protogynous H. tenuispinis (Choi et al., 2004) and M. albus
(Huang et al., 2005) and temperature sensitive O. niloticus and O.
bonariensis (Miranda et al., 2001). No intron has been found in the
ORF of EcDmrt1 (Xia et al., 2007). Rhee et al. (2008, 2011) investigated
the expression patterns of many sex differentiation related genes
in the selfi ng hermaphrodite K. marmoratus. On exposure to E 2 , the