Through his extensive breeding experiments of peas, Gregor Mendel laid the foundation of modern genetics by shedding light on the concept of 'blending intelligence', the idea that offspring inherit intermidiate characteristics between their parents. He proved that heritable variants are passed from parents to offspring and always exist in the gene even though they are not visible.
2. Draw the structure of DNA and who discovered this structure.
The double-stranded helix structure of the DNA was discovered by Watson and Crick.
3. Explain each of the five examples of variations that occur to DNA and give an example of each.
A. Substitution of a single letter for another (Point Mutation)
A point mutation is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of DNA of RNA. It usually takes place during DNA replication, a process by which one double stranded DNA molecule creates two single strands of DNA. In whippet dogs, for instance, a point mutation causes the drastic size difference between a slender one and a massive, hulking one.
B. Deletion of a block of letters
Deletion refers to a state in which a certain part of a chromosome, or a sequence of DNA, is missing. Many children with physical abnormalities are victims of microdeletion, a relatively small amount of deletion of a chromosome.
C. Duplication of new letters
Gene Duplication refers to any duplication of a part of DNA which contains a gene. Just like any other types of mutation, gene duplication is also a byproduct of errors occured during DNA replication. It is known to be a major cause of various cancers.
D. Insertion of new letters
Often caused by unequal crossover occurred curing meiosis, an insertion is defined as an addition of one or more nucleotide base pairs into a DNA sequence. A pea plant whose inserted genes cause it to be wrinkled is an example of insertion mutation.
E. Inversion/Translocation of letters already present
In an inversion mutation, the whole section of DNA becomes reversed; in a translocation mutation, the chromosome segments and the genes included there change positions.
4. What is evo-devo?
Evo-devo is one field of biology which focuses on the development of different organisms and common ancestors by studying the effects and contributions of individual developmental genes to evolution.
5. Make a connection between human migration and the mutation of lactose intolerance.
In the ancient times before 10,000 B.C, humans would naturally lose the ability to digest lactose after reaching about 4 or 5 years old. Drinking the mild of other animals therefore resulted in devastating results including severe stomach cramps and diarrhea. However, as soon as a genetic mutation of lactose intolerance which allowed one to permanently produce lactase occurred near modern day turkey, the number of lactose-tolerant people dramatically increased and successfully inherited their genes to their offspring. The group of lactose-tolerant people then migrated all throughout Eurasia, Great Britain, Scandinavia, Mediterranean, etc. Such phenomenon explains how 80 percent of Europeans became milk-drinkers.
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