8.1 Early Concepts in Genetics
| Trait - any characteristic that can be passed from parents to offspring. |
| Many modern foods are descendents of wild plants. |
| Gregor Mendel - Austrian monk and scientist whose work started "genetics". |
8.2 Mendel's Investigation
| He chose a pea plant because they had seven traits in two distinct forms. |
| Pure-bred - produce offspring with parental traits. |
| Recessive trait - trait that does not show in hybrid. |
| Gene - indicates a genetice factor that controls a trait. |
8.3 Modern Genetics
| Alleles - different versions of a gene for the same trait. |
| Law of segregation - each pair of alleles separates or segregates during meiosis. |
| Dominant allele - allele that always controls a trait. |
| Recessive allele - allele that is hidden when paired with dominant allele. |
| Law of Independent Assortment - gene pairs segregate into gametes randomly and independently of each other. |
| Genotype - genetic makeup of an organism. |
| Heterozygous - organism in which alleles are not identical. |
8.4 Probability and Genetics
| Probability - used to predict results of genetic cross. |
| P= 1/2 - probability of getting heads or tails in one flip. |
8.5 Using a Punnett Square
| Punnett square - makes it easier to predict results of genetic cross. |
| Monohybrid cross - genetic study of one trait at a time. |
| P generation of a cross between green pods (GG) and yellow pods (gg) is written GG x gg. |
| F1 generation, offspring, must have genotype of Gg. |
| Dihybrid cross - study the inheritance of two traits at a time. |
8.6 Other Patterns of Heredity
| Incomplete dominance - there are no dominant or recessive alleles. |
| Polygenic traits - traits controlled by 2 or more gene pairs. Example - color of human eyes. |
| Multiple alleles - 3 or more alleles for a trait in the population. |
| In multiple alleles, there are many different alleles for a gene in the population. |