Friday, November 18, 2011

Blue tulip/ Mendel theory of heredity, Genetic Questions?

1. At the present time, there is no suck thing as an all-blue tulip. The first one found will be quite valuable. How might a breeder increase the chances of finding a blue tulip?





2. Before Mendel, the chief theory of heredity was "blood-line inheritance." According to this theory, the parents' traits are blended in the offspring, just as two liquids blend when mixed together. Mendel's theory rested on the idea that traits are transmitted by particles (genes) and do not blend. Give evidence in support of the older theory. Then show how the results of Mendel's experiments fail to fit that theory.








Any help with these questions is greatly appreciated!

Blue tulip/ Mendel theory of heredity, Genetic Questions?
1. I can give a cool website where you try and make a "black tulip"..its actually quite tricky and takes me a while to do it, but once you see the "genotpes" shown as colours, its easier.





2. I guess the one that jumps to mind in concomplete dominance where you do get a mixing of parental characters eg red = RR, white = rr and Rr=pink





Also multiple alleles that factor in like skin colour where many alleles contribute and you can get a range anywhere in bwt the parental characters





Basically anything that is NOT controlled by complete dominance. Mendel was lucky ( or clever or both) in that the traits he chose were complete dominance where you show either the dominant or recessive trait. eg round or wrinkled seeds, tall or short......so 3 genotypes and TWO phenotypes
Reply:I can definately answer question 2 for you!


- The older theory is correct in the sense that the parents "bloodlines" do mix like two liquids that blend. Take for example a white rose and a red one- When you put them together, using the older theory, every single one of their offspring would be pink.





While Mendel proved that red roses and white roses do make pink roses, he further proved that not all their offspring would be pink thus discrediting the older theory.





Genes (or genetic particles) do play a part. Mendel discovered that when crossing a red rose with a white rose only 50% of the offspring would be pink while 25% would be white and 25% red.





While this is just a basic example (Mendel actually used pea plants and fruit flies) it illustrates Mendels theory and 1:2:1 ratio.


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