Week 3 Key Terms Flashcards
Allele
The variation or version of DNA sequences for a given section of a genomic location.
The expression of genes
Autosomal dominant inheritance
A dominant mutated gene located on an autosome (non-sex gene)
You need only one changed gene to be affected by this type of disorder. A person with an autosomal dominant disorder has a 50% chance of having an affected child with one changed gene
Huntington’s Disease
Autosomal recessive inheritance
To have an autosomal recessive disorder, you inherit two mutated genes from each parent (both parents must pass on allele). Their health is rarely affected because they have only one changed gene.
Two carriers have a 25% chance of having an unaffected child with two unaffected genes. They have a 50% chance of having an unaffected child who also is a carrier. They have a 25% chance of having an affected child with two changed genes.
Albinism, Sickle Cell Anemia
Behavioral genetics
Field of study that examines how genes and experience combine to influence the diversity of human traits, abilities, and behaviors
Traits with strong genetic components are still modified by environmental influences
Dizygotic (DZ) twins
Also know as a fraternal twin; occurs when two ova are released and each is fertilized by a different sperm; he resulting offspring share 50% of the genetic material
DNA
Deoxyribonucleic Acid; the chemical structure, shaped like a twisted ladder, that contains all of the genes; 20K-25K genes reside within our chromosomes
Down Syndrome
Also known as trisomy 21; a condition in which a third, extra chromosome appears at the 21st site. Down syndrome is associated with distinctive physical characteristics accompanied by developmental disability
Epigenetic framework
A perspective stating that development results from reciprocal interactions between genetics and the environment such that the expression of genetic inheritance is influenced by environmental forces
The epigenome is a molecule that stretches along the length of DNA and provides instructions to genes, determining how they are expressed and whether they are turned on or off
Fragile X Syndrome
An example of a dominant-recessive disorder carried on the X chromosome
1 in 20K males
Symptoms include cognitive impairment; attention problems; anxiety; unstable mood; long face; large ears; flat feet; and hyper extensible joints
Gene
A basic unit of heredity composed of DNA
Genetic counseling
A counseling session where a genetic defects and chromosomal abnormalities are determined through a family history of heritable disorders
Women over the age of 35, couples from the same ethic group, relatives have a genetic condition
Genotype
An individual’s collection of genes that contain instructions for all physical and psychological characteristics, including hair, eye color, personality, health, and behavior
Heritability
A measure of the event to which variation of a certain trait can be traced to genes
Heritability research examines the contributions of the genotype but also provides information on the role of experience in determining phenotypes
Selective breeding has revealed genetic contributions to many traits and characteristics, such as aggressiveness, emotionality, sex drive, and learning
Heterozygous
Chromosomal pair consisting of two different alleles
Whether the trait is expressed depends on the relations among genes
(Aa, aA)
Homozygous
Refers to a choromxomal pair consisting of two identical alleles
The inherited characteristic will be displayed in the offspring
(AA, aa)
Huntington’s Disease
A degenerative brain disorder that affects muscular coordination and cognition
1 in 20K people;
Usually expresses after 30+ years
Chromosome 4 mutation: repeated material
Incomplete dominance
A genetic inheritance pattern in which both genes are expressed in the phenotype
Monozygotic (MZ) twins
Also known as identical twins; occurs when the zygote splits apart early in development. The resulting offspring share 100% of their genetic material
Mutation
A sudden permanent change in the structure of genes
May be induced by exposure to environmental toxins such as radiation and agricultural chemicals in food
Niche-picking
An active gene-environment correlation in which individuals seek out experiences and environments that complement their genetic tendencies
An example of an active gene-environment correlation when children actively create experiences and environments that correspond to and influence their genetic predispositions
Phenotype
The observable physical or behavioral characteristics of a person, eye, hair color, or height
Polygenic inheritance
Occurs when a trait is a function of the interaction of many genes, such as with height, intelligence, temperament, and susceptibility to certain forms of cancer
Range of reaction
The concept that a genetic trait may be expressed in a wide range of phenotypes dependent on environmental opportunities and constraints
Although someone may have the genes to be tall, if they are malnourished, they will not fulfill their genetic potential
A genotype sets boundaries on the range of possible phenotypes, but the phenotypes ultimately displayed vary in response to different environments
Sex-linked (or X-linked) traits
Genetic disorders that affect the sex chromosome: X
Males are more likely to be affected by X-linked genetic disorders because they only have one X chromosome
Color blindness, Duchenne muscular dystrophy, Hemophilia
Sickle cell
Sickle cell alleles cause red blood cells to become crescent, or sickle, shaped
Cannot distribute oxygen effectively throughout the circulatory system
