Chao 2 Genetics, Prenatal, Dev & Birth Flashcards
Genes
The basic unit of genetic info
Zygote
The new cell formed by the process of fertilization
DNA (deoxyribonucleic acid) molecules
The substance that genes are composed of that determines the nature of every cell in the body & how it will function
Chromosomes
Rod-shaped portions of DNA that are organized in 23 pairs
Monozygotic twins
Twins who are genetically identical
Dizygotic twins
Twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time
Dominant trait
The one trait that is expressed when two competing traits are present
Recessive trait
A trait within an organism that is present, but is not expressed
Genotype
The underlying combo of genetic material present (but not outwardly visible) in an organism
Phenotype
An observable trait; the trait that is actually seen
Homozygous
Inheriting from parents similar genes for a given trait
Heterozygous
Inheriting from parents different forms of a gene for a given trait
Polygenic inheritance
Inheritance in which a combo of multiple gene pairs is responsible for the production of a particular trait
X-linked genes
Genes that are considered recessive & located only on the X chromosome
Behavioral genetics
The study of the effects of heredity on behavior
Down syndrome
A disorder produced by the presence of an extra chromosome on the 21st pair; once referred to as mongolism
Fragile X syndrome
A disorder produced by injury to a gene on the X chromosome, producing mild to moderate mental retardation
Sickle-cell anemia
A blood disorder that gets its name from the shape of the red blood cells in those who have it
Tay-Sachs disease
A disorder that produces blindness & muscle degeneration prior to death; there is no treatment