Recombination
in
Eukaryotes
Unlike prokaryotes, in eukaryotes the genes are organised onto several chromosomes which are present in the nucleus. The number of chromosomes is species specific and is a stable character of that species. Genetic recombination here is essentially a sexual process involving recombination during meiosis leading to the formation of male and female haploid gametes. Fusion of gametes results in the new types of diploids. However in the fungi there is some complexity. Unlike most eukaryotes, some only exist in the haploid state.
Consider the life cycle of two fungi. Aspergillus nidulans and Saccharomyces cerevisiae. In A. nidulans, haploid mycelia of different strains fuse and form fruit body. In this fruit body there is karyogamy and meiosis, During meiosis the chromosomes from the two nuclei pair up and recombine with each other to give hybrid chromosomes which carry genes from both parent chromosomes.
