Website Search
ID 16168

Genes come in pairs

Description:
Repeat Mendel's experiments with an eighth trait.
Transcript:
HI! You want to repeat Mendel's experiments with an eighth trait. You choose flower color. Pea plants have flowers that are white or colored. To get a pure-bred colored flower plant, you start with a colored flower plant. What should you do next? Self-fertilize this plant. If all the flowers of the next generation are colored, the plant was pure-bred. That is correct. Nothing, this is a pure-bred colored flower plant. At this point you can't tell if this is a pure-bred purple flower plant or not, try again. No, if you don't know the history of this plant, you can't tell if this is a pure-bred colored flower or not. Cross-fertilize this plant with a colored flower plant. No, you can cross-fertilize with another colored but you can't be sure of the genotypes of either plant. Cross-fertilize this plant with a white flower plant. No, if you want a pure-bred colored, you don't want to introduce a white flower gene. To get a pure-bred colored flower plant, you start with a colored flower plant, and let it self-fertilize. To get a pure-bred colored flower plant, you let a colored flower plant self-fertilize, then you plant, and grow the seeds. Most of the plants you get have colored flowers, but a few have white flowers. What should you do next? Choose several of the colored flower plants, self-fertilize them, then plant and grow their seeds. That is correct. The colored flower plants are pure-bred. No, at this point you can't tell if any of these are pure-bred colored flower plants or not. The white flower plant (after it self-fertilizes) will give pure-bred colored flowers in the next generation. A white flower plant will not give a pure-bred colored flower plant. Since not all of the offspring have colored flowers, the plant is not pure-bred. You have to repeat the self-fertilization. To get a pure-bred colored, you choose several colored flower plants, and let them self-fertilize, then you plant and grow the seeds. Many of the self-fertilized plants have some colored and some white flower offspring. You choose one of the plants from a family of all colored flower plants, let it self-fertilize, then you plant and grow its seeds. All the plants you get have colored flowers. Now what? This colored flower plant is pure-bred. That is correct. This isn't a pure-bred plant, you need to start all over again. No, you don't need to repeat the process since all the offspring have colored flowers. The white flower plant will give pure-bred purple flowers in the next generation. No, a white flower plant will not give a pure-bred colored flower plant. Congratulations! Since all of the offspring have colored flowers, you have made a pure-bred colored flower plant. CONGRATULATIONS! YOU'RE SO SMART!
Keywords:
flower color, plants, white flower, pea plants, colored flowers, pure-bred, self-fertilize genotypes, mendel, fertilization, genes, offspring, Gregor Mendel
Downloads:
Creative Commons License This work by Cold Spring Harbor Laboratory is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

Related content:

16190. Problem 4: Some genes are dominant.
Cross pure-bred pea plants to identify dominant flower color.
16180. Problem 3: Genes don't blend.
Breed pea plants to observe flower color.
16154. Animation 2: Genes Come in Pairs
Gregor Mendel explains how he discovered that genes come in pairs by studying pea plants.
16161. Gallery 2: Colored Pea Flower
The colored flower of a pea plant.
16182. Animation 4: Some genes are dominant.
Gregor Mendel explains the rules of inheritance.
16143. Animation 1: Children Resemble Their Parents
Gregor Mendel explains how traits are inherited.
16153. Concept 2: Genes Come in Pairs
Mendel deduced that pure-bred parents have two copies of the same gene for each trait.
16169. Concept 3: Gene's don't blend.
Mendel discovered that pure-bred plants did not produce offspring with blended traits.
16170. Animation 3: Gene's don't blend.
Gregor Mendel explains that breeding short and tall pea plants didn't produce a medium-sized plant.
16301. Animation 12: Evolution begins with the inheritance of gene variations.
George Shull used corn to study gene variation.
Cold Spring Harbor Laboratory
CSHL HomeAbout CSHLResearchEducationNews & FeaturesCampus & Public EventsCareersGiving