inheritance key terms Flashcards
define ‘chromosome’
a long section of DNA coiled around histones that is made up of many genes
define ‘heterozygous’
a pair of homologous chromosomes that carry the same different alleles for the same gene
define ‘gene’
a section of DNA which codes for a particular polypeptide
define ‘locus’
the position of a gene on a chromosome
define ‘allele’
an alternative version of a gene
define ‘genotype’
the combination of alleles that an organism has for a particular trait
define ‘phenotype’
observable characteristics of an organism
define ‘dominant’
allele that is always expressed if present
define ‘recessive’
allele that is only expressed if there is no dominant allele present
what is monogenetic inheritance?
inheritance of a characteristic that is controlled by only 1 gene, usually with just 2 alleles
- eg inheritance of cystic fibrosis
define ‘homozygous’
a pair of homologous chromosomes that carry the same alleles for a gene
define ‘codominant’
both alleles are equally dominant and both are expressed in phenotype
- eg roan cow
define ‘multiple alleles’
more than 2 alleles for a single gene
define ‘sex linkage’
gene whose locus is on x chromosome
define ‘autosomal linkage’
genes located on same chromosome
