Unit 2 Flashcards
Chromosomes
Threadlike structures in the nuclei of cells that contain genetic material.
Autosomes
First 22 pairs of chromosomes. They control the inheritance of an organism’s characteristics except for the sex-linked ones.
Sex Chromosomes
The 23rd chromosome pair; these determine the sex of the child.
Deoxyribonucleic Acid (DNA)
Molecule composed of four nucleotide bases that is the biochemical basis of heredity.
Gene
Group of nucleotide bases that provides a specific set of biochemical instructions.
Genotype
The complete set of genes that makes up a person’s heredity.
Phenotype
Physical, behavioral, and psychological features that results from the interaction between one’s genes and the environment.
Alleles
Variations of genes.
Homozygous
When the alleles in a pair of chromosomes are the same.
Heterozygous
When the alleles in a pair of chromosomes differ from each other.
Dominant
Form of an allele whose chemical instructions are expressed phenotypically.
Recessive
Form of an allele whose instructions are ignore in the presence of a dominant allele.
Incomplete Dominance
Situation in which one allele does completely not dominate another.
(ie. Individuals who have one dominant and one recessive allele for sickle-cell anemia will have the sickle-cell trait.)
Phenylketonuria (PKU)
Inherited disorder in which the infant lacks an important liver enzyme, which converts phenylalanine (an amino acid found in dairy products, bread, diet soda, and fish) into tyrosine. This accumulation of phenylalanine poisons the nervous system, resulting in mental retardation (Diamond et al., 1997; Mange & Mange, 1990).
Huntington’s Disease
Progressive and fatal type of dementia caused by dominant alleles. Characterized by progressive degeneration of the nervous system.
Behavioral Genetics
The branch of genetics that studies the inheritance of behavioral and psychological traits.
Polygenic Inheritance
When phenotypes are the result of the combined activity of many separate genes.
Monozygotic Twins
The result of a single fertilized egg splitting to form two new individuals; also called identical twins.
Dizygotic Twins
The result of two separate eggs fertilized by two sperm; also called fraternal twins.
Heritability Coefficient
A measure (derived from a correlation coefficient) of the extent to which a trait or characteristic is inherited.
Niche-picking
Process of deliberately seeking environments that are compatible with one’s genetic makeup.
Nonshared Environmental Influences
Forces within a family that make siblings different from one another.
Zygote
Fertilized egg, created when a sperm cell penetrates an egg.
In Vitro Fertilization
Process by which sperm and an egg are mixed in a petri dish to create a zygote, which is then placed in a woman’s uterus.
Preimplantation Genetic Screening (PGS)
A procedure used to test the heredity of an egg fertilized with assisted reproductive technology, typically to determine the presence of genetic disorders.