Biology 1a Genetics Terms Fall 2012 Genetics – study of inheritance of characteristics. Genomics – looking at the human body in terms of multiple, interacting genes. Karyotype – chromosome chart that displays the 23 chromosome pairs in size order. Autosomes – chromosomes that do not carry genes that determine sex. Sex Chromosomes – chromosomes ( X and Y) that include genes that determine sex. Alleles – genes for the same trait that exist in variant forms. Homozygous – two identical alleles for a particular gene. Heterozygous – two different alleles for a particular gene. Genotype – the particular combination of alleles in a person’s genome. Phenotype – the appearance or health condition of the individual that develops as a result of the ways the genes are expressed. Wild type – associated phenotype is normal function or the most common expression in a particular population. Mutant – a change from wild type, producing an uncommon phenotype. Dominant – allele whose action masks that of another allele. Recessive – allele whose expression is masked. Pedigree – a diagram that depicts family relationships and known genotypes and phenotypes. Incomplete dominance – the heterozygous phenotype is intermediate between that of either homozygote. Codominant – different alleles that are both expressed in a heterozygote.