LS2 Genetics Vocab

heredity

the passing of genetic information from parent to offspring

trait

a specific characteristic that can vary from one individual to another

gene

a segment of DNA on a chromosome

allele

a version of a gene (example: one red bean OR one white bean)

dominant allele

an allele whose trait always shows up in the organism when the allele is present; it covers up the recessive

recessive allele

an allele that is hidden whenever the dominant allele is present

homozygous

to have two of the SAME alleles for a gene (example: AA or aa)

heterozygous

to have two DIFFERENT alleles for a gene (example: Aa or RW)

self-pollination

when sperm cells in pollen fertilize the egg cells in the same flowering plant

true-breeding plant

a plant that will always produce offspring with the same form of a trait when it self-pollinates

genotype

the combination of alleles/letters inherited for a particular gene; (example: AA or Aa or aa)

phenotype

the physical expression (observable trait) due to inherited alleles; (example: white fur or no fur)

acquired trait

trait that is learned rather than inherited

codominance

an inheritance pattern where BOTH alleles for a gene are expressed/dominant when the organism is heterozygous (example: red flower + white flower = red and white flowers)

polygenic trait

trait controlled by two or more genes

complete dominance

an inheritance pattern where the dominant allele completely masks the effect of the recessive allele when the organism is heterozygous; (example: fur bunny mom and no fur bunny dad = baby bunny with fur)

selective breeding

process of breeding organisms that results in offspring with desired genetic traits; AKA artificial selection

chromosome

A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

cell nucleus

the spherical central structure of a cell that contains the chromosomes

punnett square

chart/way to predict possible offspring genotypes and phenotypes