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Genetics Vocab
| Question | Answer |
|---|---|
| monohybrid cross | a cross that involves one pair of contrasting traits. |
| true-breeding | organisms/genotypes that are homozygous for a specific trait. always produce offspring with that trait. |
| trait | specific characteristics that vary from one individual to another. |
| hybrids | the offspring of crosses between parents with different traits. |
| alleles | the alternative forms of a gene that govern a characteristic, such as hair color. |
| dominant | describes the trait that is expressed of two different alleles. |
| recessive | a trait or an allele that is expressed only when two recessive alleles for the same characteristic are inherited. |
| 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. |
| law of independent assortment | the law that states that genes separate independently of one another in meiosis. |
| sex-linked trait | a trait that is determined by a gene found on one of the sex chromosomes, (X or Y in humans) |
| Punnett square | a graphic used to predict the results of a genetic cross. |
| homozygous (pure) | describes an individual that has identical alleles for a trait on both homologous chromosomes. |
| heterozygous (hybrid) | describes an individual that has two different alleles for a trait. |
| phenotype | an organism’s appearance or other detectable characteristic that results from the organism’s genotype and the environment. |
| genotype | the entire genetic makeup of an organism; also the combination of genes for one or more specific traits. |
| Parental generation (P1 generation) | the first two individuals that mate in a genetic cross. |
| F1 generation | the first generation of offspring obtained from an experimental cross of two organisms. |
| F2 generation | the second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation. |
| incomplete dominance | form of inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype. |
| codominance | both alleles for a gene are fully expressed. |
| multiple alleles | more than two alleles (versions of the gene) for a genetic trait. |
| polygenic traits | characteristics of an organism that is determined by many genes. |
| test cross | the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype. |
| probability | the likelihood that a possible future event will occur |
| pedigree | a diagram that shows the occurrence of a genetic trait in several generations of a family. |