Costly anti-predator traits tend to be expressed only in high-predation conditions. For the cyprinid fish genus Carassius, deeper body depth is more adaptive to avoid predation by gape-limited piscivorous fish, but it raises swimming costs. It is therefore predicted that the relative body depth will decrease when the prey fish has reached a size larger than the predator gape-size. This predicti...

In current screening test for Down’s syndrome (namely maternal serum alpha-fetoprotein-AFPhuman chronic gonadotropinhCG-, unconjugated estriol plus maternal age) an elevated level of hCG is an important predictor of fetal aneuploidy (1). The positive predictive value of the multiple marker screening test is approximately 4.3% (2). Besides Down’s syndrome, triploidy, trophoblastic diseases, and ...

We modify the Penna Model for biological aging, which is based on the mutation-accumulation theory, in order to verify if there would be any evolutionary advantage of triploid over diploid organisms. We show that this is not the case, and that usual sex is always better than that involving three individuals.