Figure 1

Transmission frequencies of Spam1-Hyal5 BAC transgenes in hemizygotes of three lines, Tg8, Tg9, and Tg11, reveal a distortion only for Tg8/+. a) Histograms showing the rate of production of transgenic and non-transgenic progeny analyzed at weaning on Day 21. Tg8-A represents the progeny of the founder and 3 F₁ hemizygous males, while progeny from F₂-F₄ hemizygous males are seen in Tg8-B. Tg8-T represents the total progeny analyzed for the Tg8 line. There is a significant deviation from 1:1 for Tg8-A (χ² = 27.30; P < 0.001), Tg8-B (χ² = 17.47; P < 0.001), and Tg8-T (χ² = 41.8; P < 0.001) all represented by an asterisk; while there was no difference in 1:1 ratios (P > 0.05) for Tg9 and Tg11, represented by the diamond. b) The TRD for Tg8/+ mice does not result from post-zygotic selection against transgene-bearing zygotes, as revealed by the average litter sizes of transgenic lines. In addition to the BAC transgenic lines we included a Spam1 cDNA transgenic line, Cinn (179), which like Tg9 and Tg11 also had a 1:1 ratio in the progeny. The means for the litters ranged from 6.68 to 8.50 and are shown at the top of the histograms with their SDs at the sides. The highest mean, 8.50 ± 1.51, was seen for Tg8A which had the highest TRD, 2.8:1.