You are here : / / / 6 Reasons Why Your Gums are Bleeding. If you regularly see red when you brush your teeth, it could be cause for concern. Here's why your gums are bleeding ' and what to do about it. Jackie Middleton.
Between 1856 and 1863 Mendel cultivated and tested some 29,000 pea plants (Pisum sativum). This study showed that one in four pea plants had purebred recessive alleles, two out of four were hybrid and one out of four were purebred dominant.
Mendelâs model system: The pea plant. Mendel carried out his key experiments using the garden pea, Pisum sativum, as a model system. Pea plants make a convenient system for studies of inheritance, and they are still studied by some geneticists today. Useful features of peas include their rapid life cycle and the production of lots and lots of seeds.