He found that when he bred red-flowered plants with white-flowered plants, all the offspring produced red flowers. If he bred these plants with each other, most of the offspring had red flowers, but some had white. This was because the allele for red flowers is dominant , and the allele for white flowers is recessive.
One of Mendel's observations was that the inheritance of each characteristic is determined by 'units' that are passed on to descendants unchanged. The genetic diagram shows all of the possible alleles for a particular characteristic. Dominant alleles are capital letters, while the recessive alleles are lower-case letters. Among the many species on which Mendel worked, he selected pea because the plants and seeds have a wide array of distinct features that occur in two easily identifiable forms e.
The pea flower is another useful feature of these plants , as it ensures that the flowers of the hybridised and parent plants are protected from any foreign pollen.
The relatively short growth period is another advantage, meaning there was not a long wait for the results.
Over eight years, Mendel studied pea traits one at a time and crossbred variants to systematically record how traits were passed on from one generation to the next: a mammoth task that involved approximately 28, pea plants. For example, he cross-bred pea plants with round, yellow seeds and plants with wrinkled, green seeds. Only the dominant traits yellow and round appeared in the F1 progeny, but all combinations of trait were seen in the self-pollinated F2 progeny.
The traits were present in a ratio round, yellow: round, green: wrinkled, yellow: wrinkled, green. Miko, I. Nature Education 1 1. Retrieved on 5 July from Nature Education. Learn more about Gregor Mendel's principles, alleles and inheritance on the Biology Online website. Add to collection. Genes located on different chromosomes will be inherited independently of each other. Go to full glossary Add 0 items to collection. Download 0 items.
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