This research aims to discover the right physiological age of fertilized egg for tetraploid induction and the parameters of heat shock treatment in Heteropnestus fossilis. The heat shock parameters are shock temperature (39°C, 40°C, and 41°C); time at which the shock is initiated (23 to 28 min after fertilization) and for a duration of 1, 2 and 3 min. The confirmations of tetraploid were based on chromosome counting. The result indicates that the window time to start the heat shock treatment for maximum tetraploid induction is 25 to 27 min after fertilization at an ambient water temperature of 27°C. Shock treatment at 40°C and for 2-min duration, stated at 27 min after fertilization has shown highest tetraploid induction, i.e. 28% (p &lt;.05) with 76% survival. Tetraploids form the main source for the induction of higher ploidy levels. © 2019, © 2019 Taylor &amp; Francis.

Godwin Christopher J

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Vellore Campus

Siva R

Department of Biotechnology

Ezilrani P.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

The effect of heat shock and timing on the induction of tetraploidy in Catfish, Heteropnestus fossilis

Journal of Applied Aquaculture

This study reports the results on induced meiotic diploid gynogenesis and female homogametic nature in the Indian catfish, Heteropneustes fossilis. The eggs of H. fossilis were inseminated with conspecific sperm. The sperm suspension was diluted to 1 × 107 sperm mL-1 in Hanks balanced salt solution. Sperm were irradiated under UV light, with the exposure time ranging from 15 to 360 s (7500 ergs mm-2 for 60 s). The genetic inactivation of paternal chromosomes was confirmed by chromosome counting from the larval cells and the larvae also had a characteristic haploid syndrome. A typical 'Hertwig effect' in the yield of hatched larvae was observed with doses of UV exposure &gt;75 s (9375 ergs mm2). Larvae resulting from sperm UV irradiated above 120 s (15 000 ergs mm2) were 100% haploids. Application of heat shock to the activated eggs was effective in suppressing the release of the second polar body (meiotic gynogenesis) and resulted in diploid gynogenetic larvae morphologically identical to those of the control. The best yield of diploid gynogens (49.3% with respect to the control) was found to be at 6 min after egg activation and the heat shock at 41 °C for a 1-min duration, at an ambient water temperature of 27 °C. A total of 113 diploid gynogenetic fry from seven different female fish were reared and subjected to sexing. All gynogenetic fish were female in contrast to the control, which had a mean sex ratio of 56.7% females (which was not significantly different from 50% female). From these results, the sex determination mechanism in H. fossilis was presumed to be female homogamety. © 2010 The Authors. Aquaculture Research © 2010 Blackwell Publishing Ltd.

Aquaculture Research

Induction of meiotic gynogenesis in the stinging catfish Heteropneustes fossilis (Bloch) and evidence for female homogamety

Aquaculture

Drastic mortality in tetraploid induction results from the elevation of ploidy in masu salmon Oncorhynchus masou

Developmental & Comparative Immunology

Demonstration of hematopoietic stem cells in ginbuna carp (Carassius auratus langsdorfii) kidney

Nature Reviews Genetics

The advantages and disadvantages of being polyploid

Induction of triploidy and tetraploidy in stinging catfish, Heteropneustes fossilis (Bloch), using heat shock

Journal	Journal of Applied Aquaculture
Publisher	Informa UK Limited
ISSN	1045-4438
Open Access	0