@article{parks_eisen_parker_hester_murray_2000, title={Correlated responses to selection for large body size in oMt1a-oGH transgenic mice: reproductive traits}, volume={75}, ISSN={["0016-6723"]}, DOI={10.1017/S001667239900436X}, abstractNote={Correlated responses in female reproductive performance were evaluated following short-term 
selection within full-sib families for increased 8-week body weight in two replicates of four lines of 
mice: two ovine metallothionein–ovine growth hormone (oMt1a-oGH) transgene-carrier lines, one 
from a high-growth background (TM) and one from a control background (TC), and two non-transgenic lines, one from each of these genetic backgrounds (NM and NC, respectively). A fifth 
line (CC), not containing the transgene, served as a randomly selected control. The initial 
frequency of the oMt1a-oGH transgene construct in the TM and TC lines was 0·5. The frequency 
of transgenic females sampled at generations 7 and 8 of selection was 84·0% and 6·1% in the TC 
and TM lines, respectively. No significant female infertility differences were detected between 
transgene-carrier and non-transgenic lines or between transgenic and non-transgenic mice within 
carrier lines, whereas high-growth background lines had a higher infertility than control 
background lines (P < 0·05). Correlated responses in the TC transgene-carrier line were suggestive 
of reduced reproductive performance as indicated by increased post-implantation mortality 
(P < 0·05), number of dead fetuses plus implants (P < 0·05), and loss of fetuses from day 16 to 
parturition (P < 0·001). For the first two traits, the negative correlated responses were accounted 
for by the reduced performance of transgenic compared with non-transgenic females. Embryos 
carrying the transgene may also have a lower viability. In contrast, the NC non-transgenic line did 
not exhibit reduced reproductive performance for these traits. The low frequency of the transgene 
in the high-growth background TM line was associated with reduced fitness and a lower additive 
effect for 8-week body weight compared with the control background TC line.}, number={2}, journal={GENETICAL RESEARCH}, author={Parks, KR and Eisen, EJ and Parker, IJ and Hester, LG and Murray, JD}, year={2000}, month={Apr}, pages={199–208} }