Biology Reference
In-Depth Information
hermaphrodites can change from primary males to females and females
to primary IP males and secondary TP males. Hence these sex changes are
radically different from those among gonochores, in which the phenotypic
morphotypes change at the best from sneaker male to satellite male,
satellite male to territorial male and/or territorial male to pirate male—all
these changes occur within a single sex namely male. Thus the changes in
morphotypes are
intrasexual
among gonochores but are
intersexual
among
hermaphrodites. This generalization may implicate that the fl exibility/
plasticity of sex determination and differentiation processes are several
times greater among hermaphrodites than among gonochores.
Incidentally, the gonadal differentiation in primary gonochoric fi shes
implies the loss of bisexual potency by the germ cells supporting somatic
cells. On the other hand, the bisexual potency is retained by the somatic
cells of the secondary gonochores and hermaphrodites, whose brains are
not sexualized with the presence and activity of radial glial cells, as in
zebrafi sh. Yet the hermaphrodites are not monophyletic and are suggested
to have arisen independently in more than 10 lineages (Warner et al.,
1978). Expectedly, the bisexual potency of the somatic cells in the few
but widely diverse group of hermaphrodites, presumably also remains
diverse. For instance, not all the females of
P. pagrus
(see Fig. 52) undergo
natural sex change throughout their life time. The same holds true of the
protandrics like
Diplodus
vulgarus
(see Pandian, 2010). Does it mean that the
bisexual potency of the somatic cells is lost in them?
P. pagrus
is amenable
for rearing in laboratory (Kokokris et al., 1999). It is then for the French
neuroendocronologists to investigate the presence and activity of radial
glial cells of the red porgy; for it seems that the radial glial cells control the
retention of bisexual potency by the germ cells supporting somatic cells.
