Emigration and Immigration
Americas
Geography
Africa, Northern
Genetics, Population
Chromosomes, Human, Y
Population Dynamics
Haplotypes
DNA, Mitochondrial
Climate
Gene Flow
The change in gene frequency in a population due to migration of gametes or individuals (ANIMAL MIGRATION) across population barriers. In contrast, in GENETIC DRIFT the cause of gene frequency changes are not a result of population or gamete movement.
Africa
I'm afraid there seems to be a misunderstanding - "Africa" is not a medical term and does not have a medical definition. Africa is the world's second-largest and second-most populous continent, consisting of 54 countries with diverse cultures, peoples, languages, and landscapes. If you have any questions related to medical topics or definitions, I would be happy to help answer those for you!
Ethnic Groups
Biological Evolution
Cell Movement
Animal Migration
Gene Frequency
Evolution, Molecular
Cell Migration Inhibition
Phenomenon of cell-mediated immunity measured by in vitro inhibition of the migration or phagocytosis of antigen-stimulated LEUKOCYTES or MACROPHAGES. Specific CELL MIGRATION ASSAYS have been developed to estimate levels of migration inhibitory factors, immune reactivity against tumor-associated antigens, and immunosuppressive effects of infectious microorganisms.
Foreign-Body Migration
Sequence Analysis, DNA
Genotype
Cell Migration Assays
Cells, Cultured
Macrophage Migration-Inhibitory Factors
Chemotaxis
Signal Transduction
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.