Indian Society of Genetics & Plant Breeding
Genetically uniform strains/inbred strains of animals are
used in experiments that demand minimal genetic
background variability and highly reproducible results.
Modern genomic research is heavily dependent on inbred
strains and they are widely used for identification of
quantitative loci that affect evolutionarily and biomedically
important traits, dissection of gene-gene and gene
environmental interaction patterns, toxicity studies,
immunology, reverse genetics, cancer research, etc. In mice,
over 450 inbred strains have been described and in medaka
over 13 inbred strains have been established. Owing to its
numerous attributes zebrafish, Danio rerio, is one of the
widely studied vertebrate model organisms, but comparable
zebrafish inbred strains are not available to the scientific
community. This is because of early onset of inbreeding
depression causing high mortality of embryos and larvae
and biased sex ratio that have been reported from earlier
attempts to produce inbred lines. At CZeBraG-Centre for
Zebrafish Breeding and Genetics Research facility of ICARCIFE, the inbred lines of zebrafish are being developed.
The strategy followed is intense inbreeding coupled with
strong positive selection for selected traits. The base
population consisted of three wild stocks of zebrafish
collected from rivers of North East India. Using nested
mating design 84 families were produced in F1 generation
and 46 inbred families were produced in F2 generation.
Genetic parameters for growth traits like body weight and
standard length were estimated. The overall heritability for
body weight and standard length was estimated using
animal model and found to be 0.43 ± 0.05 and 0.36 ± 0.04
respectively. Fecundity was also recorded but showed no
significant variation among stocks. Inbreeding depression
was studied by comparing the population means for body
weight and standard length of F1 and F2 generation. The
analysis suggested there was no inbreeding depression.
Genetic monitoring of zebrafish is conducted using
microsatellite markers. New PCR primers were designed
for 20 selected microsatellite loci with high stringency. High
Resolution Melting Curve analysis was used for genotyping
individual zebrafish. In addition to developing inbred lines
the centre is also maintaining the wild zebrafish stocks
and has commenced supply of pedigreed zebrafish for
researchers. In future zebrafish of known inbred levels (12.5
to 50% and above) can be supplied. Currently, the CZeBraG
can house about 10000 adults, with separate facility for
holding individual fish.
Keywords: Zebrafish, inbreeding, inbred strain
Year: 2019
Volume: 79
Issue: 1, Supplement
Article DOI: 10.31742/IJGPB.79S.1.4
Print ISSN: 0019-5200
Online ISSN: 0975-6906
Mujahidkhan A. Pathan*, Aparna Chaudhari and Gopal Krishna info_circle
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