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Genetics, Chromosomal Abnormalities, Prenatal Dev and Childbirth

Genes basic units of genetic instructions, which are segments of DNA molecules
Chromosome thread-like structures of DNA; there are 46 (23 pairs)
DNA deoxyribonucleic acid; made of units called genes; double stranded helix held together by bases
Natural selection individuals with genetically controlled characteristics reproduce more successfully and the species comes to resemble those individuals more and more as time passes
Genotype genetic characteristics; the sum total of all the genes a person inherits for any particular trait
Phenotype physical expression of genetic characteristics; actual expression of traits, observable in the person’s physical appearance, as well as behavior tendencies.
Polygenic traits those traits produced by the combined action of more than one gene
Multifactorial traits those traits influenced by many factors including the environment
Additive sum of contribution of the genes involved
Dominant genes the genes that control the trait
Recessive genes the genes are carried on the genotype but not expressed in the phenotype
Reaction range is a term used to describe the range of phenotypes for each genotype, suggesting the environment’s restrictiveness or enrichment
Monozygotic twins identical twins; identical genetically
Dizygotic twins fraternal twins; different genetically
Down’s Syndrome most common chromosomal abnormality; it results from 3 chromosomes at sight 21
Phenylketonuria (PKU) abnormal protein digestion that is caused by recessive gene
Fragile X syndrome part of the X chromosome is attached by such a thin string of molecules that it seems about to break off
implantation body of cells arrive at uterus and burrow into uterine lining
teratogens any substances or conditions that contribute to birth defects
Created by: 241152