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Genetics Vocab
| Term | Definition |
|---|---|
| 1. heredity | the passing of genetic traits from parent to offspring |
| 2. Genetics | the science of heredity and of the mechanisms by which traits are passed from parents to offspring |
| 3. monohybrid | a cross between individuals that involves one pair of contrasting traits |
| 4. P generation | parental generation, the first two individuals that mate in a genetic cross |
| 5. F1 generation | the first generation of offspring obtained from an experimental cross of two organisms |
| 6. F2 generation | the second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation |
| 7. allele | one of the alternative forms of a gene that governs a characteristic, such as hair color |
| 8. dominant | the expressed form of a trait |
| 9. recessive | the trait that is not expressed when the dominant form of the trait was present |
| 10. homozygous | describes an individual that has identical alleles for a trait on both homologous chromosomes |
| 11. heterozygous | describes an individual that has two different alleles for a trait |
| 12. genotype | the entire genetic makeup of an organism; also the combination of genes for one or more specific traits |
| 13. phenotype | an organism's appearance or other detectable characteristic that results from the organism's genotype and the environment |
| 14. law of segregation | Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete |
| 15. law of independent assortment | the law that states that genes separate independently of one another in meiosis |
| 16. Punnett square | a graphic used to predict the results of a genetic cross |
| 17. test cross | the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotypes |
| 18. probability | the likelihood that a possible future event will occur in any given instance of the event; the mathematical ratio of the number of times one outcome of any event is likely to occur to the number of possible outcomes of the event |
| 19. pedigree | a diagram that shows the occurrence of a genetic trait in several generations of a family |
| 20. sex-linked traits | a trait that is determined by a gene found on one of the sex chromosomes, such as the X chromosomes or the Y chromosomes in humans |
| 21. polygenic trait | a characteristic of an organism that is determined by many genes |
| 22. incomplete dominance | a condition in which a trait in an individual is intermediate between the phenotype of the individual's two parents because the dominant allele is unable to express itself fully |
| 23. multiple alleles | more than two alleles (versions of a gene) for a genetic trait |
| 24. codominance | a condition in which both alleles for a gene are fully expressed |
| 25. vaccine | substance prepared from killed or weakened pathogens and introduced into a body to produce immunity |