The process by which characteristics of living CELLS are passed on during replication. The basis of heritability is the genetic code, contained within the DEOXYRIBONUCLEIC ACID (DNA) of all cells. Before cell division, DNA is duplicated and copies of the GENES are inherited by the daughter cells. While most genes are preserved between organisms of the same species, small differences between organisms in the exact structure of DNA lead to variations in gene structure.
These differences are manifest in variations in physical character istics such as eye or hair colour. Organisms which reproduce sexually receive one set of CHROMOSOMES from each parent, each containing half the ALLELES present in each parent. As a result, some allelic variations in gene structure may not be inherited in every offspring. The heritability of psychological traits—the ‘NATURE-NURTURE’ debate—remains a controversial issue. The relative contribution of genetic, as opposed to environmental factors as determinants of, for example, INTELLIGENCE, is unresolved.
FIONA M.INGLIS
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