Population study on the inheritance of Lac‐Z gene in transgenic mice

Summary Two populations were created, one experimental, descended from transgenic (bacterial Lac‐Z gene) founder males and the second control, descended from nontransgenic males. The transgenic and nontransgenic males were mated to females obtained from a population mated at random over many generations. In each population and each generation, body weight at the age of 21 and 42 days, weight gains, fertility and prolificacy — litter size at birth, at the age of 21 and 42 days were examined. In the experimental population the frequency of transgenic animals was calculated. In the seventh generation the frequency of transgenic animals was 30%. The results presented here indicate that for most of the traits examined, descendants of transgenic males proved to be of poorer quality than those with nontransgenic sires. The results suggest that the transgenic genotype of the dam has a negative effect on the growth traits. The fertility of both transgenic and nontransgenic animals was high and amounted to nearly 100%. Zusammenfassung Eine experimentelle Population ausgehend von transgenen (bakter. Lac‐Z Gen) Gründer‐Vätern und eine Kontrolle, von Nicht‐transgenen Vätern stammend, wurden erstellt. Männchen wurden über 7 Generationen an Weibchen aus einer panmiktischen Population gepaart und in jeder Generation Körpergewicht bei 21 bzw. 42 Tagen, Zuwachs, Fruchtbarkeit und Wurfgröße bei Geburt, 21 und 42 Tagen erhoben. In Generation 7 war die Frequenz transgener Tiers 30%. Nacuhkommen transgener Vatertiere hatten geringere Leistungen als jene nicht‐transgener Väter. Der transgene Genotyp von Muttertieren wirkte sich ungünstig auf Wachstum aus. Fruchtbarkeit aller Tiere war zufrieden stellend.