The chicken Very-Low-Density Apolipoprotein II (apoVLDL II) gene is specifically expressed in liver in response to estrogen. In this study, we performed a functional analysis of the 300-base pair region immediately 5' to the gene by gene transfer of chloramphenicol acetyl transferase (CAT) constructs into chicken embryonic hepatocytes (CEH). Two estrogen response elements (EREs) could be distinguished which together form a potent estrogen response unit. Stimulation of transient expression by co-transfection with a plasmid expressing rat C/EBP confirmed that a similar protein in chicken liver may be involved in apoVLDL II transcription. In vitro DNaseI footprinting and band-shift analysis with liver, oviduct and spleen nuclear extract revealed the tissue distribution of the proteins binding to the promoter region. A liver-specific protein bound to multiple sites of which some resembled the recognition sequence of the CCAAT/Enhancer binding protein, C/EBP. Of the other proteins binding to the apoVLDL II promoter, one was identified as the liver-specific LF-A1 by mobility shift analysis, using purified bovine LF-A1, and another as the general COUP-transcription factor, using an antiserum against the human COUP-TF.

Strains of Drosophila melanogaster having different alcohol dehydrogenase (Adh) genotypes (FF, FS, or SS) were assembled in a mating chamber in varying ratios, and the mating successes were recorded. In experiments with a 25:25 ratio, the FF males succeeded in mating more than did FS and SS males, while the FS males surpassed the SS males. As for the females, FF also surpassed SS. In experiments with a 5:45 or 45:5 ratio, some differences from the 25:25 ratio occurred, but in these cases the rare genotypes were at a disadvantage. In one case, female genotypes (FF vs. SS) displayed a difference in mating latency time, but male genotypes did not. The findings did not suggest that rare genotype mating advantage and overdominance in mating success play a role in the maintenance of the Adh polymorphism.

Multiple choice mating experiments were carried out with the alcohol dehydrogenase (Adh) genotypes FF and SS of Drosophila melanogaster. Rearing conditions and age of the flies were varied. The large mating advantage of FF for 4-6 days old flies, reared at 25°C, found by Pot et al. (1980), was confirmed. This advantage decreased or even disappeared when rearing temperature or age of the flies was lowered. The relative humidity during rearing also influenced mating success. The relevance of these results for the maintenance of the Adh polymorphism is discussed.