ELECTROPHORETIC VARIATIONS IN ISOESTERASES OF THE TWO CATFISH SPECIES, CLARIAS GARIEPINUS AND CLARIAS ANGUILLARIS, IN THE EGYPTIAN FRESHWATER

ELECTROPHORETIC VARIATIONS IN ISOESTERASES OF THE TWO

CATFISH SPECIES, CLARIAS GARIEPINUS AND CLARIAS

ANGUILLARIS, IN THE EGYPTIAN FRESHWATER

By

SHNOUDYA. BAKHOUM*AND MOHAMED A. SAYED-AHMED

~NationalInstitute ofOceanography and Fishen·es. Alexandria. Egypt
Key words: Esterase, Genetic distance, Catfish, Egypt.
ABSTRACT
Esterase isozymes were compared electrophoretically, using three
organs; liver, spleen and kidney to determine the phylogenetic relationship
between Clarias garlevinus and C. amzuillaris, as well as, to lmow the
genetic differences between two types of C .f!arievinus to verify their
genetic isolation by estimating the genetic distance between types and lor
species of genus Clarias. The results indicated that the genes controlled
esterase isozymes were six lOCi in C garievinus and five loci in C
anguillaris, whereas the locus Est-2C was ‘1ompletely absent in all organs
ofC anf!Uillaris. Moreover, anodal loci were the only ones that expressed
in all studied samples, and the locus Est-2 A showed higher activity than
other loci in all specimens.
The overall genetic identity and genetic distance between these tow
species were 0.81 and 0.19 respectively. The maximum magnitudes of
genetic identity (Gl==0.99) and minimum genetic distance (GD==O.Ol) were
found between types ofC garievinus. The lowest genetic identity between
C anf!uillaris and type A (Gl= 0.87) and type B (GI== 0.80) were appeared
in spleen, while the lowest genetic distance (GD=0.02) between them were
found in kidney and liver, respectively. The combined genetic identity and
genetic distance between types A and type B of C garievinus and C.
anguillaris were not similar, whereas they equal GI = 0.81, GD = 0.19
andGI = 0.78, GD = 0.22 respectively.