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Name: Sara
Status: student
Grade: 12+
Location: Outside U.S.
Country: Canada
Date: Summer 2013


Question:
Hi, I beginning to understand the all food, example fruits have DNA as well. All DNA is different , like apple DNA is different from banana DNA. But if we have two bananas, would both their DNA be different? Similar? Same?



Replies:
Hi Sara,

Thanks for the question. Yes, DNA is found in the seeds of fruits such as apples and bananas. Two bananas would have similar, but not exactly identical DNA. DNA contains the base pairs A, T, C, and G. The sequence of these base pairs in DNA is what carries the genetic information. Two bananas chose at random would have different sequences of these base pairs. However, the number of base pairs in each banana would be almost the same.

To push your question even further, did you know that identical twins do not have exactly the same DNA? As the DNA replication process is not 100% error free, there is a small probability that identical twins will not have exactly the same DNA.

I hope this helps. Please let me know if you have more questions. Thanks Jeff


Sara,

All living organisms share DNA that consists of nucleotides arranged in a way that defines a species. In every organism there is a set amount of core genes that make it viable. However, within a species there is a small percentage of differences between "siblings". Many plants can reproduce both sexually (seeds) and asexually (vegetative cloning). If there were two bananas from the same genus and species that were reproduced sexually, there should be a slight difference in their nucleotides but not enough differences to make them something other than bananas. When plants reproduce asexually (or clone) they pass 100% of their alleles to their offspring. In a stable environment, asexual reproduction has advantages since the plant is well suited for the environment and mature plants are not as frail as seedlings. The disadvantage is that asexual reproduction puts a plant at risk for local extinction from new pests and diseases. Commercial growers breed what is sold in stores to be consistent because consumers expect their bananas to look like bananas. Vegetative reproduction (cloning), which is used for commercially grown bananas, results in genetically identical bananas.

Judy Luke


First of all, let's make sure we have our definitions straight. DNA is a chemical made of 4 types of subunits: A, T, C, and G's. There is nothing unique about the chemical DNA between any two organisms. What makes my DNA and your DNA different is the sequence of the letters. It's like taking the alphabet that is made of the same 26 subunits and rearranging them differently to make different words. So two organisms of the same species will have very similar sequences, but will differ here and there by a few letters. The more related the organisms are, the more similar their DNA will be.

vanhoeck



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