Sexual reproduction requires chromosomal content to be halved in the sex cells to produce haploid gametes
- The process by which haploid gametes are created is called meiosis (meiosis I is the reduction division)
- Fusion of two haploid gametes creates a diploid zygote that can then grow and develop via mitotic division
If meiotic formation of haploid gametes did not precede fertilisation, chromosomal content would double every generation
- Polyploidy is a condition whereby an organism has more than two complete sets of chromosomes in all cells (i.e. > diploid)
- Polyploidy is far more common in plant species which lack separate sexes and are capable of self-pollination
- Polyploidy is very rare in animal species due to the consequences of having extra allele copies of every gene
Kirby Genetics #2: Sexual Reproduction via Meiosis or Mitosis
