ANT340H5 Lecture 8: Lecture 8.docx
Document Summary
Late 19th century: people notices some skeletal variants occurring in families. Gruneberg (1952) skeletal variants in mice: no strict correlation between parents and offspring, no strictly mendelian inheritance. Berry & berry (1967: same study in humans. Non metric: non measured; since they are scored. Discrete trait: usually scored p/a or by type. Discontinuous/quasicontinuous trait: underlying continuum that is expressed as p or a depending on genetic and environmental factors. Epigenetic: genetic and environmental component to their expression. Gruneberg (1952) 3 rd molar in mice. Expression is discrete: 3rd molar is p or a. Formation is quasicontinuous: depends on combination of factors. Formation of 3rd molar depends on size of tooth germ: under control of several genes, act together to affect overall size, if size reached, 3rd molar forms, if size not attain, 3rd molar is not formed. Model explaining the process of expressing epigenetic traits physiological threshold: interaction between genetic potential and developmental/environmental factors, trait is expressed.
