BACKGROUND The high frequency of aneuploidy sperm raises concerns that there may be an increased incidence of aneuploid offspring in ICSI programmes. In order to assess the role that chromosome complement plays in normal and abnormal fertility, detailed molecular cytogenetic studies must be done on sperm samples from men with normal and abnormal fertility. METHODS To understand more clearly t...

Many genetic networks are astonishingly robust to quantitative variation, allowing these networks to continue functioning in the face of mutation and environmental perturbation. However, the evolution of such robustness remains poorly understood for real genetic networks. Here we explore whether and how ploidy and recombination affect the evolution of robustness in a detailed computational mode...

According to the ‘masking hypothesis’, diploids gain an immediate fitness advantage over haploids because diploids, with two copies of every gene, are better able to survive the effects of deleterious recessive mutations. Masking in diploids is, however, a double-edged sword: it allows mutations to persist over time. In contrast, deleterious mutations are revealed in haploid individuals and are...

DNA replication in G2 does not normally occur due to the checkpoint control. To elucidate its mechanism, the functions of the escargot and Dmcdc2 genes of Drosophila were studied. When escargot function was eliminated, diploid imaginal cells that were arrested in G2 lost Cyclin A, a regulatory subunit of G2/M cdk, and entered an endocycle. escargot genetically interacted with Dmcdc2 which encod...

The linkage learning genetic algorithm (LLGA) proposed by Harik (Harik 1997), evolved tight linkage in a bid to solve difficult problems. This paper extends this work to difficult nonstationary problems. The probabilistic expression mechanism of the LLGA is akin to the dominance and polyploidy found in nature. This redundancy of gene expression found in the LLGA was found to benefit the adaptat...

This paper presents a new crossover operator for genetic programming – dominance crossover. Dominance crossover is similar to the use of dominance in nature. In nature, dominance is used as a genotype to phenotype mapping when an organism carries pairs (or more than one) chromosome, but here we use dominance on a haploid structure. The haploid form contains all the information relevant to the p...