Genetic studies on sex determination and colouration in Nile tilapia (Oreochromis niloticus L.)
Yazarlar (1)
| Makale Türü | Özgün Makale (Uluslararası alan indekslerindeki dergilerde yayınlanan tam makale) | ||
| Dergi Adı | |||
| Makale Dili | – | Basım Tarihi | 05-1999 |
| Makale Linki | https://www.storre.stir.ac.uk/handle/1893/21428 | ||
| UAK Araştırma Alanları |
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| Özet |
| The present study was undertaken to investigate colour and sex determination mechanisms through the application of androgenesis, gynogenesis and controlled breeding programme with the objective of producing all red males in 0. niloticus. The highest yield of androgenetic haploid to pigmentation stage was 24.6±3.5% (relative to controls) with optimal UV irradiation dose of 450Jm"2 for 5 minutes. The highest survival rate of diploid androgens was 0.07±0.07% (relative to controls) to yolk sac stage using a heat shock of 42.5°C for 3 minutes 30 seconds applied at 25 minutes after fertilisation. All paternal inheritance of diploid androgenetic tilapia was verified using DNA fingerprinting. The mean recombination frequency of the red skin colour gene in meiotic gynogens was 0.12±0.04. All maternal inheritance of meiotic gynogens was verified using the isozyme locus ADA*. Analyses of sex ratios of meiotic gynogens suggested that male progenies were produced by an epistatic sex determining locus (SDL-2 with two alleles SR and sr) causing female to male sex reversal in the homozygous phase (srsr) but with limited penetrance. A close linkage was found between a sex determining locus (SDL-2) and the red gene. No significant difference was found between colour genotypes (namely homozygous red, heterozygous red and wild type) in terms of total fecundity, ISI (inter spawning interval), egg size and survival rate. Overall mean ISI was 26.3±1.0 days. Mean total fecundity was 1096 eggs. Fecundity varied over successive spawns but this variation did not appear to be related to spawning periodicity. Hormonal and thermal feminisation were … |
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