effects of prolonged selection for behavior on the stress response and activity of the reproductive system of male grey mice (Rattus norvegicus)

• Published in: Russian journal of genetics Vol. 50; no. 8; pp. 846 - 852
• Main Authors: Prasolova, L. A, Gerbek, Yu. E, Gulevich, R. G, Shikhevich, S. G, Konoshenko, M. Yu, Kozhemyakina, R. V, Oskina, I. N, Plyusnina, I. Z
• Format: Journal Article
• Language: English
• Published: Moscow Springer-Verlag 2014; Pleiades Publishing
• Subjects: Animal Genetics; Animal Genetics and Genomics; behavior modification; Biomedical and Life Sciences; Biomedicine; captive animals; Human Genetics; humans; males; mice; Microbial Genetics and Genomics; morphometry; rats; Rattus norvegicus; stress response; testes; testosterone; Testosterone Level; Morphometric Index; Corticosterone Level; Rattus Norvegicus; Sexual Maturation
• ISSN: 1022-7954; 1608-3369
• DOI: 10.1134/S1022795414080031

Two Norway rat (Rattus norvegicus) populations contrasting in behavior have been raised at the Institute of Cytology and Genetics, Novosibirsk, Russia with long-term selection for the absence or enhancement of an aggressive response towards humans. They are designated as tame and aggressive, respectively. In this work we investigated the effects of the selection on behavior, stress responsiveness, and function of testes in males of the 78th generation. It is shown that the difference between the strains in their response to humans remains the same as in previous generations. However, the differences in stress response and rate of maturation contradict earlier data. For the first time, we note a higher glucocorticoid-mediated response to restriction stress and retarded sexual maturation in tame rats compared to aggressive ones, according to morphometric indices of gonads and testosterone levels. It is conceivable that the change in selection effects is determined by the disjunction of the directions of selection for behavior and the modification of the stress response. This study is the first to characterize males recently (six or seven generations of propagation in captivity) caught in the wild with regard to the indices under consideration and used as a control group. Wild rats have the highest stress response and rate of sexual maturation as compared to those selected.