Biology Reference
In-Depth Information
B
A
D
C
Fig. 59.
Expression of
goosecoid
gene at 12 hour post-fertilization in (A) control embryos of
goldfi sh and (b-d) heat shock—treated embryos. Embryos were treated at 40
o
C for (B) 30
seconds, (C) 60 seconds and (D) 90 seconds at 5 minutes post-fertilization. Arrow heads indicate
the reception of signal of
gsc
. Bar = 1 mm (from Yamaha et al., 2002)
In the context of global warming, Ytteborg et al. (2010) exposed
during the period from the egg stage to 60 g body size of
S. salar
to low
temperature at 10ºC and high temperature at 16ºC. In the fi sh exposed to
higher temperature, faster growth disrupted the differentiation of bone and
cartilage cells resulting in a signifi cantly higher frequency of deformities in
spinal column than in those reared at 10ºC. The increased risk of developing
vertebral deformities was linked to an altered gene transcription, especially
the down-regulation of extracellular matrix (
ECM
) genes like
Colla1,
Osteocalcin
and
decorin.
Exposing the 5- and 10- d old fry of
O. mossambicus
to selected temperatures (20-33ºC) for fi ve days, Wang and Tsai (2000) also
noted that exposure of 5-day old fry at high temperature (28-32ºC) alone
caused a high percentage of deformity. Gavaia et al. (2002) recognized
high number of malformations both in the caudal complex and vertebral
column of
Solea senengalis
. About 44% of the individuals showed at least
one deformity. Of them 28% deformities were in vertebral column.
The study of Gorman et al. (2007) on the mutant guppy
P. reticulata
Curveback
syndrome stands as a unique example for a better understanding
of the spinal stability and deformity. Due to extreme phenotypic variability,
very little progress has been made to identify the etiology of idiopathic
