Genetics
21 definitions in this category
Allele One of two or more alternative forms of a gene that arise by mutation and are found at the same position on a chromosome... Bottleneck (Population) A sharp reduction in population size that reduces genetic diversity. Surviving individuals' genes become overrepresented... Chromatin The complex of DNA and proteins (mainly histones) that makes up chromosomes. How DNA is packaged inside the cell nucleus... Chromosome A structure of tightly coiled DNA and proteins that carries genetic information. Humans have 46 chromosomes (23 pairs);... Diploid Having two complete sets of chromosomes, one from each parent. Most animal cells are diploid; gametes (sex cells) are ha... Epigenetics Heritable changes in gene expression that occur without changes to the underlying DNA sequence. Chemical modifications t... Founder Effect A loss of genetic variation that occurs when a new population is established by a very small number of individuals from... Gene A sequence of DNA that encodes instructions for building a specific protein or RNA molecule. Genes are the basic units o... Genome The complete set of genetic instructions in an organism, encoded in DNA (or RNA in some viruses). The genome includes al... Genotype The complete genetic makeup of an organism—the specific combination of alleles it carries. The genotype is the underlyin... Germline The cell lineage that produces reproductive cells (eggs and sperm). Only genetic changes in germline cells can be inheri... Horizontal Gene Transfer The movement of genetic material between organisms other than by parent-to-offspring inheritance. Common in bacteria, it... Inheritance The transmission of genetic information from parents to offspring. Inheritance determines which traits are passed betwee... Methylation The addition of a methyl group to DNA or proteins, often silencing gene expression. A key epigenetic mechanism that does... Mutation A change in DNA sequence that alters genetic information. Mutations can be harmful, neutral, or beneficial, and are the... Phenotype The observable physical, physiological, or behavioral characteristics of an organism, resulting from the interaction of... Phenotypic Plasticity The ability of an organism to change its phenotype (observable characteristics) in response to environmental conditions,... Pleiotropy When a single gene affects multiple phenotypic traits. Changes to pleiotropic genes have cascading effects throughout th... Somatic Relating to body cells as opposed to reproductive (germline) cells. Somatic cells make up the body's tissues and organs;... Trait A distinguishing characteristic or quality of an organism. Traits can be physical (eye color), physiological (blood type... Weismann Barrier The principle that genetic information passes only from germline (reproductive) cells to somatic (body) cells, never in...