Question
NOVA-Secrets in our DNA 1. (2:10) What do consumer DNA test kits help reveal about ourselves? 2. (6:15) How is DNA inherited from our ancestors? What percentage of DNA do we acquire from each of our parents? 3. (7:05) What are centimorgans? How does it help us determine our relationship with other individuals? 4. (7:30) Why are centimorgans just an indicator of a POSSIBLE relationship between two individuals? 5. (12:45) What is the "DNA code" made of? 6. (12:50) How many base pairs make up our complete genome? 7.(13:22) What are single nucleotide polymorphisms (SNPs) , and why are they important when comparing DNA between two different individuals? (turn over)
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Vaughn
Professional ยท Tutor for 6 years
Answer
1. Consumer DNA test kits can reveal information about a person's ancestry, including their ethnic origins and the migration patterns of their ancestors. They can also identify living relatives who have also taken the same DNA test. Some tests offer insights into potential health predispositions, although this information should be interpreted with caution and in consultation with a healthcare professional. They can also sometimes reveal unexpected family secrets, such as adoptions or previously unknown siblings.2. DNA is inherited through chromosomes passed down from our parents. We inherit half of our DNA from our mother and half from our father. Each parent contributes 23 chromosomes, resulting in a total of 46 chromosomes in the offspring.3. A centimorgan (cM) is a unit of measurement that describes the genetic distance between two locations on a chromosome. It's a measure of the likelihood of recombination (the shuffling of genetic material) occurring between those two points. In the context of genealogy, the number of centimorgans shared between two individuals can be used to estimate the closeness of their biological relationship. Higher shared centimorgans generally indicate a closer relationship.4. Centimorgans are just an indicator of a *possible* relationship because the same amount of shared DNA can be inherited through different pathways. For example, you might share a certain number of centimorgans with someone who is your second cousin, but you might also share a similar number with someone who is a more distant relative through a different ancestral line. The same amount of shared DNA doesn't always equate to the same relationship. Furthermore, recombination is a random process, so even siblings won't inherit exactly the same segments of DNA from their parents.5. The "DNA code" is made of four chemical bases: adenine (A), thymine (T), guanine (G), and cytosine (C). These bases pair up in a specific way: A with T, and G with C. The sequence of these base pairs along the DNA molecule determines the genetic instructions.6. The human genome is made up of approximately 3 billion base pairs.7. Single nucleotide polymorphisms (SNPs) are variations in a single base pair in a DNA sequence. For example, one person might have a "C" at a specific location, while another person might have a "T." SNPs are the most common type of genetic variation among people. They are important when comparing DNA between individuals because they can be used to identify shared ancestry, trace disease susceptibility, and predict responses to drugs. By comparing the SNPs of two individuals, scientists can estimate how closely related they are and identify segments of DNA that they have inherited from common ancestors.