Estimation of the mode of inheritance of thermal tolerance in the guppy Poecilia reticulata

Abstract

High water temperature influences the survival, growth, and maturation of fish. Genetically characterizing thermal tolerance is one of the most important subjects in fish culture. To identify the genetic characterization of thermal tolerance, this characteristic was compared among strains, and among parents and their offspring, in the guppy Poecilia reticulata. In the strain comparison, significant differences in survival rate were observed among the five strains examined, and between females and males. Females exhibited greater tolerance than males in four of five strains examined. In the comparison between parents and their offspring, stronger influence of female parent than of male parent was observed. Offspring obtained from surviving females exhibited greater tolerance than those from dead females. This tendency was typically observed in male offspring. The survival rate in male offspring obtained from dead female parents was lower than that of those from surviving females. The high-temperature tolerance of male parents did not influence this characteristic in offspring as strongly as that of female parents. These results suggest that the major gene or genes, which has a dominant resistant allele and a recessive sensitive allele, are probably passed on by sex-linked inheritance, located on the X chromosome.

Thermal tolerance of the crab Pachygrapsus marmoratus: intraspecific differences at a physiological (CTMax) and molecular level (Hsp70)

“…As females occur in greater shore heights, where they are exposed to terrestrial conditions and a greater variability of the environmental factors, they showed higher CTMax values and a greater magnitude of the molecular response. Combining our study with other scientific papers reveals that sexual dimorphism in stress tolerance and Hsp70 production seems to occur across several taxa (e.g., Mills and Fish 1980;Afonso et al 2003;Winne and Keck 2005;Nakajima et al 2009;Mikulski et al 2011). …”

“…It was found that females had a higher CTMax value and higher Hsp70 production than males. Higher tolerance for females when exposed to stress has also been found in other ectotherms (e.g., Mills and Fish 1980;Afonso et al 2003;Winne and Keck 2005;Nakajima et al 2009;Mikulski et al 2011). …”

“…There is contradictory evidence on intraspecific differences in thermal tolerance in ectotherms. Some authors did not find any differences (e.g., Du et al 2000;Badillo et al 2002) while others did (e.g., Gaston and Spicer 1998;Strange et al 2002;Nakajima et al 2009). There is a need to deepen intraspecific studies in order to understand how species react to thermal stress.…”