Genetics Intro

Phenotype Observable, Physical traits (ear shape, petal color) these are expressed biologically. –Offspring usually have a phenotype similar to their parents’. –Environmental factors play a critical role example Japanese children of early and middle 1900’s. Better diets taller children. The result of a genetic plan influenced by environment.

Simple Inheritance Dominant trait – expresses itself in an organism and can be observed. Recessive trait – does not express itself but organism carries the trait. –Cannot express itself due to dominant gene being present –Organism does exhibit trait if inherits recessive genes from both parents

Genotype The basic genetic plan, all the genetic information in an organism. –Stored as DNA (deoxyribonucleic acid) molecules –Chromosome – cell structures that include all DNA molecules organized around structural proteins. –Gene – Particular piece of genetic information found on the chromosome

Genes Humans have 23 pairs (46) chromosomes –Contain many genes –Largest 3,000 genes –Smallest, the Y-chromosomes contains only 230 genes Allele – Different versions of the same gene. (ex. Blood Type) –The combination determines the organisms phenotype

Alleles One comes from the father and one from the mother Example Blood Types –Dad Type A –Mom Type B –Child Type AB Combination is Heterozygous (different) Child Type AA Homozygous (same)

Extra Credit Questions Are exhibited dominant traits Homozygous or Heterozygous? Are exhibited recessive traits Homozygous or Heterozygous? 5 points each