tailieunhanh - Báo cáo sinh học: "Selection on testis size as an indicator of maturity in growing animals. I Direct and correlated responses in growth"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Selection on testis size as an indicator of maturity in growing animals. I Direct and correlated responses in growth | Genet Sei Evol 1990 22 231-246 Elsevier INRA 231 Original article Selection on testis size as an indicator of maturity in growing animals. I Direct and correlated responses in growth WG Hill1 PJ Marks1 JC Jenkins1 RB Land2 1 Institute of Animal Genetics University of Edinburgh West Mains Road Edinburgh EH9 SJN 2 AFRO Institute of Animal Physiology and Genetics Research Edinburgh Research Station Roslin Midlothian EH25 9PS UK Received 2 October 1989 accepted 15 February 1990 Summary - Selection was undertaken in mice to test whether gonad size specifically testis weight could be used to indicate degree of maturity and produce genệtic change in the shape of the growth curve from records on young animals only. Selection was practised for 11 generations high and low on 5 wk male body weight lines on 5 wk testis weight XH XL and on indices with these traits selected in the same HH LL and in opposite HL LH directions. There were 2 replicates of each selection line and 4 unselected controls. Divergences between high and low lines within family standard deviation units for 5 wk body weight and testis weight respectively were HX-LX and XH-XL and HH-LL and and HL-LH and . There were minor changes in shape of the growth curve in the direction expected with those selected for high testis weight showing earlier maturity. A simple measure 6 wk weight 15 wk weight for entire males wis HX LX 67 3 XH XL 69 é HH LL HL Ln averaging for lines selected for high testis weight and for low compared to for controls. In castrate males a similar pattern of changes in growth curve was observed indicating that they were not a consequence of testis derived hormones. Mice selected for high testis weight were leaner than those selected for low testis weight. Thus growth curves changed due to selection on testis weight but it was not established if this is because testis size is an indicator of sexual maturity. .

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