Lecture 5 Flashcards
(18 cards)
What factors contribute to phenotypic variability?
Phenotypic variability is influenced by both genes and environmental factors. DNA alone does not explain the entire variability.
Mnemonic (back of card):
Visualize a plant growing differently in sunlight versus shade, representing how the environment shapes the phenotype.
What is the continuum in disease susceptibility?
Disease susceptibility is a continuum where both genetic and environmental factors play a role. Natural selection affects replication errors.
Mnemonic (back of card):
Think of a gradient of colors from “genetic” to “environmental,” showing how disease susceptibility varies.
What is the difference between Mendelian and complex disorders?
Mendelian disorders have rare mutations that are necessary and sufficient for large phenotypic effects.
Complex disorders involve common mutations and polymorphisms that are neither necessary nor sufficient, leading to small phenotypic effects.
Mnemonic (back of card):
Picture Mendelian disorders as “sharp mountains” (clear and distinct) and complex disorders as “gentle hills” (gradual and varying).
What is an example of a Mendelian disorder?
Huntington’s disease is an example of a Mendelian disorder with large phenotypic effects.
Mnemonic (back of card):
Imagine the gradual buildup of symptoms over time, like a clock ticking down to the onset of Huntington’s disease.
How is a pedigree used in genetics?
A pedigree is used to trace the inheritance of genetic traits within families, showing how disorders are passed down.
Mnemonic (back of card):
Visualize a family tree with branches marking different generations, showing where traits appear.
What is the inheritance pattern of autosomal dominant disorders?
Autosomal dominant disorders usually have at least one affected parent, affect both genders, and have a 50% chance of passing to offspring.
Example: Huntington’s disease.
Mnemonic (back of card):
Picture a coin flip, symbolizing the 50% chance of inheriting the disorder.
How do autosomal recessive disorders inherit?
Autosomal recessive disorders are inherited when both parents are carriers. The chances of an affected child are 25% after one affected child.
Example: Cystic fibrosis, sickle-cell anemia.
Mnemonic (back of card):
Visualize two “carrier” parents as puzzle pieces coming together to create a 25% chance of an affected offspring.
What are the characteristics of X-linked recessive disorders?
X-linked recessive disorders affect mainly males, have no male-to-male transmission, and are passed by asymptomatic carrier mothers.
Example: Hemophilia, red-green color blindness.
Mnemonic (back of card):
Imagine a male inheriting a genetic trait from his mother, visualized as a “female carrier passing down a gene.”
How are X-linked dominant disorders inherited?
X-linked dominant disorders affect both genders, but females show more variable phenotypes. Affected females have a 50% chance of passing the disorder to children.
Example: Rett syndrome.
Mnemonic (back of card):
Visualize a female as the “connector” passing the trait to both daughters and sons.
How do Y-linked disorders inherit?
Y-linked disorders affect only males, and all sons of an affected father will also be affected. There is no transmission to daughters.
Example: Male infertility.
Mnemonic (back of card):
Picture a father passing a “Y” symbol directly to his sons, but not to his daughters.
What is DNA fingerprinting?
DNA fingerprinting is a technique used to identify individuals based on their unique DNA patterns.
Mnemonic (back of card):
Imagine a fingerprint made of DNA strands, uniquely identifying each individual.
What was the Human Genome Project?
The Human Genome Project was an initiative to map the entire human genome, which provides insights into genetic diseases and variations.
Mnemonic (back of card):
Picture a map of the human body with each section representing different genes.
What are the ethical considerations of cloning?
While animal and human cloning are scientifically possible, there are ethical concerns, such as eugenics and the morality of selecting or creating people based on genetic traits.
Mnemonic (back of card):
Visualize a “choose your traits” menu, representing the ethical dilemmas in genetic selection.
How do genetics and the environment contribute to disease?
Both genetic factors and environmental influences contribute to diseases, such as Cystic Fibrosis, Alzheimer’s, and Stroke. The gene-environment interaction is crucial for understanding disease susceptibility.
Mnemonic (back of card):
Imagine a Venn diagram with overlapping circles for “Genes” and “Environment,” showing their combined effect on disease.
What is the difference between Mendelian and complex disorders in terms of genetic variation?
Mendelian disorders involve rare mutations that are necessary and sufficient for large phenotypic effects.
Complex disorders involve common mutations and polymorphisms, which contribute to small phenotypic effects but are neither necessary nor sufficient alone.
Mnemonic (back of card):
Visualize a large “mountain” (Mendelian) versus “rolling hills” (complex disorders), representing large vs. small effects.
How do you construct a pedigree for genetic counseling?
Pedigrees are used to track inheritance patterns of genetic traits in families. Guidelines ensure consistent nomenclature to describe relationships and inheritance across generations.
Mnemonic (back of card):
Picture a family tree with symbols representing males, females, affected individuals, and carriers, branching out through generations.
What was the goal of the Human Genome Project?
The Human Genome Project aimed to map the entire human genome, providing a comprehensive understanding of genetic diseases and genetic variation across populations.
Mnemonic (back of card):
Imagine a globe with dots marking each gene location, representing the mapping of the human genome.
What are the ethical concerns surrounding cloning and eugenics?
Cloning and eugenics raise ethical questions about the morality of selecting or altering genetic traits in humans and animals, such as the potential for genetic discrimination.
Mnemonic (back of card):
Picture a balance scale with “science” on one side and “ethics” on the other, weighing the implications of genetic manipulation.
