Why did Mendel carry out cross-pollination to obtain hybrid seeds?
Important Questions on Heredity: from Parents to Offsprings
Some pea plants bear white flowers while some other bear purple flowers. Mendel selected such varieties of plants, obtained their seeds and grew more plants from them. He now allowed self-pollination to take place in plants of a particular variety. (that is- those with white flowers and those with purple flowers). Each time he selected the flowers on the basis of their colour, he carried out this process for some generations till he could ensure that seeds of plants with purple flowers would yield only purple flowers while those with white flowers would obtain white. Thus, by the process of repeated self-pollination, Mendel obtained plants that would produce seeds of purple or white varieties respectively for several generations. Mendel called these varieties pure. He started his experiments with these varieties of pure plants. He sowed seeds of pure varieties of white and purple plants. As the plants grew and started flowering he cross-pollinated them. The seeds obtained from cross-pollinated flowers, or the hybrid seeds, yielded varieties that bore only purple flowers. This generation of plants obtained from parental varieties of pure plants was first generation (F1 generation) plants.
Think why intermediate varieties (those between purple and white) may not have obtained.
The 11th pair of autosomal chromosome has the factors responsible for the formation of the protein haemoglobin.
What is the function of this protein?
See figure what do you think are the probability of each of the four conditions XY, XY, XX, and XX?
What do you think is the probability of having a female child?
