Concept

Keywords

All living things reproduce. Offspring may closely resemble but are not identical to their parents, from whom they inherit genetic traits. The units of inheritance are called genes and contain the genetic information. Individuals receive two copies of each gene, one from each parent, but the two genes may not be identical. For simple genetic traits, the two inherited copies of a gene determine the phenotype for that trait. Other genetic traits are determined by more than one gene.

Reproduction. The reproductive system. Genotype. Phenotype. Dominant. Recessive. Pedigree analysis. Polygenic trait. Homozygote. Heterozygote.

The genetic information is contained in DNA molecules, which have a unique double-helical structure and a four-letter informational code.

DNA structure. Double-stranded helix. Nucleotides. DNA sequencing. Base-pairing. Complementarity.

Chromosomes are long pieces of DNA that consist of linear arrangements of genes and other DNA. Sexually reproducing organisms have two sets of chromosomes in most cells of their bodies. Each parent contributes one of each pair of chromosomes to its offspring randomly.

Linkage. Gene mapping. Ploidy. Homologous chromosomes. Segregation. Assortment. Variation. Meiosis. Probability.

Together with the environment, an organism's genes influence its appearance and characteristics.

Genotype gives rise to pheno-type. Acquired vs. inherited traits. Environmental factors. Nature vs. Nurture. Penetrance.

The DNA information in genes provides instructions for building proteins. Proteins carry out life functions and are a diverse collection of molecules that includes hormones, enzymes, structural proteins, and antibodies.

Central dogma. The genetic code. Gene expression. RNA. Transcription. Translation. Amino acids.

Cells are the building blocks of every organism's body. Each cell of an organism contains the same genetic information, which is passed on faithfully when cells divide. Different types of cells arise because they use different parts of the information, as determined by the cell's history and immediate environment. Different cell types may be functionally organized into tissues and organs.

DNA replication. Cell division. Mitosis. Differentiation. Gene expression. Cancer.

There are genetic differences between individuals of the same species. Any one gene can have alternate forms, called alleles. Changes in the DNA, or mutations, cause new alleles to arise. New alleles or new combinations of genes can lead to variation among the individuals within a population. Some variations may confer a survival or reproductive advantage under specific environmental conditions.

Mutagen. Evolution. Species. Biodiversity. Individuality. Genetic disorders.

Genetics research has applications in many fields, for example, in medicine, agriculture, biotechnology, and environmental science.

Biotechnology.

Genetics research raises many ethical, legal, and social issues; it is important for everyone to develop skills to address these issues.

Genetic testing. Pre-natal diagnosis. Genetically engineered products. Animal cloning. Genetic privacy. Maintaining biodiversity.