Nutrigenomics Flashcards
What is Nutrigenomics?
The study of how food affects a person’s genes and how a person’s genes affect the way the body responds to food. Nutrigenomics is used to learn more about how genes and diet together may affect a person’s health and risk of developing diseases, such as cancer. It may also help find new ways to prevent and treat disease.
Briefly explain Mendelian Inheritance.
Mendelian inheritance refers to certain patterns of how traits are passed from parents to offspring. These general patterns were established by the Austrian monk Gregor Mendel, who performed thousands of experiments with pea plants in the 19th century. Mendel’s discoveries of how traits (such as color and shape) are passed down from one generation to the next introduced the concept of dominant and recessive modes of inheritance.
Name Mendel’s 5 “Laws of Heredity.”
- Each characteristic corresponds to a single gene.
- Genes occur in pairs, one on each of a paired set of chromosomes.
- Each parent provides one member of each pair of its genes.
- Individual genes are inherited randomly.
- Some traits or characteristics are “dominant” while others are “recessive.”
What is a “dominant” trait?
A trait is considered dominant if it is expressed even though only one member of a pair of chromosomes carries it’s gene.
Define heterozygote.
An individual having two different alleles of a particular gene or genes, and so giving rise to varying offspring.
Define allele.
One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Define homozygote.
An individual having two identical alleles of a particular gene or genes and so breeding true for the corresponding characteristic.
What is a “recessive” trait?
A trait is considered recessive if it is expressed only when both members of a pair of chromosomes carries its gene.
Define phenotype.
The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
What are the 6 basic patterns of Mendelian inheritance?
- Autosomal dominant inheritance.
- Autosomal recessive inheritance.
- X-linked recessive inheritance.
- X-linked dominant inheritance.
- Y-linked inheritance.
- Mitochondrial (or matrilineal) inheritance.
Briefly explain autosomal dominant inheritance.
At least one parent carries the gene for the expressed phenotype. This form of inheritance affects both sexes equally and the gene may be transmitted by either the mother or the father.
Briefly explain autosomal recessive inheritance.
Both parents carry the gene for the expressed phenotype. Unless a parent is homozygous for the trait, he or she will not express the phenotype (heterozygotes do not express the phenotype).
Briefly explain X-linked recessive inheritance.
This inheritance predominantly affects males. Parents usually are unaffected (the mother is typically an “asymptomatic” carrier of the affected gene). There is no male-to-male transmission.
Briefly explain X-linked dominant inheritance.
This inheritance predominantly affects females as an affected male will always transmit the trait to his daughters but to none of his sons.
Briefly explain Y-linked inheritance.
This inheritance only affects males. All sons of an affected father are affected.
Briefly explain Mitochondrial (or matrilineal) inheritance.
This inheritance results from the inheritance of mitochondria from the maternal egg, never from the paternal sperm.
What is a Single Nucleotide Polymorphism?
Single nucleotide polymorphisms, frequently called SNPs (pronounced “snips”), are the most common type of genetic variation among people. Each SNP represents a difference in a single DNA building block, called a nucleotide. For example, a SNP may replace the nucleotide cytosine (C) with the nucleotide thymine (T) in a certain stretch of DNA.
List the 4 nucleotides that make up DNA.
DNA is made up of four building blocks called nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C). The nucleotides attach to each other (A with T, and G with C) to form chemical bonds called base pairs, which connect the two DNA strands.
Each nucleotide pairs with one other. Please list the pairings for both DNA and RNA.
Adenine pairs with Thymine
Guanine pairs with Cytosine
Uracil pairs with Adenine
List the nucleotides that make up RNA.
RNA is made up of four building blocks called nucleotides: adenine (A), guanine (G), cytosine (C), and Uracil (U).
To be classified as a SNP, the variation must be found in at least __% of the population.
1%
True or False?
SNPs always affect a gene’s function.
False
Most commonly, SNPs are found in the DNA between genes. They can act as biological markers, helping scientists locate genes that are associated with disease. When SNPs occur within a gene or in a regulatory region near a gene, they may play a more direct role in disease by affecting the gene’s function.
What are the two most studied copies of the MTHFR gene?
C677T and A1298C
What is Methylenetetrahydrofolate reductase?
Commonly referred to by it’s abbreviation, MTHFR is a gene that is crucial for proper methylation, a process that affects many aspects of our health including detoxification, neurotransmitter production, and immune function.
