[Variability of gamete thermoresistance and heat selection of gametes in frogs and molluscs].
The variability of heat resistance of gametes in amphibians and molluscs has been analysed in terms of the problem of direct thermal selection at presygotic stages of ontogenesis. A high variability in gamete heat resistance was revealed both within the frame of a population of animals and in a particular individual. The variability in gamete resistance of an individual animal was as great as 6-8 fold, whereas that within a population reached 8-10 fold value. Because of this phenomenon, a similar heat damaging factor exerted on gametes of different individuals results in different effect towards developed offsprings. A high variability of gamete heat resistance makes possible an effective and widely modified heat selection of gametes both of various genotypes and of an individual genotype. Under certain conditions gametes may be subject to natural selection, eliminating some classes of gametes and gives preference to some others. Because of this process the ratio of various phenotypes in population of organisms developed from the selected gametes also changes. The selective elimination of gametes of poikilotherms is able to influence the genetical-physiological structure of population.
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
V B
VB
Andronikov
R A
RA
Pasynkova
I M
IM
Pashkova
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D005260:Female; D014644:Genetic Variation; D008297:Male; D008974:Mollusca / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D011896:Rana temporaria / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*; D013696:Temperature
Variabel'nost' termorezistentnosti i teplovoĭ otbor gamet liagushek i molliuskov.