Biology Reference
In-Depth Information
Fig. 7.
Oryzias latipes
: Upper panel: M = DNA marker. Transgenic XX individuals have only
the
Dmy
HNI
allele, whereas XY individuals have both
Dmy
HNI
and
Dmy
d-rR
alleles. Lower panel:
First row: The secondary sexual characteristics and body coloration of the
Dmy
transgenics.
Note the larger size and shape of dorsal and anal fi ns (white arrow heads) in males. Second
row: Histologic sections of gonads. A and D = XX female; B and E-E
1
= XX medaka with testis
and C and F-F
1
XY male. ED = efferent duct. Scale D, E
1
and F
1
= 200 µm E and F = 50 µm
(from Matsuda et al., 2007.
Dmy
gene induces male development in genetically female (XX)
medaka fi sh. Proc Natl Acad Sci, USA, 104 : 3865 - 3870. Copyright 2007 National Academy
of Sciences, USA)
(i)
sox9
: The
sox
family of genes encodes transcription factors containing
the
Sry
related HMG box, a DNA binding motif of approximately 79
amino acids. At least 20
sox
genes have been identifi ed and are sub-
divided into 10 groups A to J based on their sequences and are involved
in a wide range of developmental process including sex determination
and neurogenesis (Bowles et al., 2000).
sox9
is classifi ed into group E
and has a transactivation domain in its C terminus (Sudback et al.,
1996). The
sox9
identifi ed in medaka encodes 487 amino acids and
shows 70% amino acid identity with known vertebrate sox9 proteins.
In zebrafi sh (Chiang et al., 2001) and medaka (Yokoi et al., 2002),
sox9a
is expressed in the testes but
sox9b
in the ovary. In
O. mykiss,
sox9a1
shows sexually dimorphic expression (Vizzanio et al., 2007).
The full length of
sox9b
of guppy
Poecilia reticulata
coding sequence
is 1,443 bp and encodes for a protein of 480 amino acids. The
sox9b
of the guppy has 88% and 91% similarity to those of
G. aculeatus
and
