Glossary

Spotteddog Interactive BioStudio:Genetics

Glossary

allele-(uh-LEEL) A different form of a gene.

dihybrid cross-(DY-HY-brid) A cross between two parental varieties differing in two traits. Example BbSs x Bbss-two traits, Black coat and Spotted coat.

dominant allele- The form of the gene that is fully expressed in the phenotype. Written with an upper case letter, such as BB or Bb

gamete-(GAM-eet) A haploid egg or sperm cell; gametes unite during sexual reproduction to create a diploid zygote (soon to become a little baby)

gene- One of many discrete units of hereditary information located on the chromosomes and made up of DNA.

genotype-(JEE-noh-type) The genetic makeup of an organism-'what the genes are'

heterozygous- (HET-ur-oh-ZY-gus) Having two different alleles for a given trait. Example-Bb

homozygous-(HOME-oh-ZY-gus) Having two identical alleles for a given trait. Example-BB or bb

hybrid-an organism that is the offspring of two different varieties

law independent assortment- Mendel's second law, stating that each allele pair segregates independently during gamete formation;applies when genes for two traits are locatied on different pairs of homologous chromosomes.

monohybrid cross-(MON-oh-HY-brid) A cross between two parental varieties differing in only one trait. Example Bb x BB- one trait for a Black coat.

phenotype-(feh-NEH-type) The physical and physiological makeup of the organism 'what you see, how the genes are expressed'

progeny-(PROJ-eh-nee) offspring, descendents, kin

Punnett Square- a handy device (a type of diagram) for pedicting the results of a genetic cross.

recessive allele- The form of the gene which is not dominant. In a heterozygote, it is not fully expressed in the phenotype. Written with a lower case letter, bb or Bb.

cassava-(kah-sah-vah) A tropical plant with starchy roots from which tapioca is obtained

tapioca-(tap-ee-oh-kah) A starchy substance in hard white grains obtained from cassava and used for making puddings

Sources:
Biology (4th Edition) Campbell, N.A., The Benjamin/Cummings Publishing Co.,Inc.:Menlo Park, CA ,1996.
Oxford American Dictionary (Heald Colleges Edition) E. Ehrlich, S.B.Flexner, G. Carruth, J.M. Hawkins, Inc., Oxford University Press: New York, NY,1980.