Segregation ratios are consistent with diploidy. The seeds of others give a mixture of tall and short plants. Two-thirds of the tall plants continued to segregate short plants on further selfing and analysis of the progeny. Observation 1 Plants that do not give mixtures when selfed are said to be homozygous for the tall trait. Those that produce mixtures are said to be heterozygous .
Heterozygous individuals produce segregating populations.
The short character is said to be recessive , while the tall character is dominant . Recessive genetic characters are not modified when in the presence of the dominant character, but can be recovered on further crossing. The segregation of differentiating traits is Mendel's First Law. Union of the haploid gametes results again in a diploid organism with two copies. Many fundamental genetic concepts stem from G. Mendel's work on pea genetics.