Scientists found members of a plant species they did not recognize. They wanted to determine if the unknown species was related
1 answer:
Complete question:
Scientists found members of a plant species they did not recognize. They wanted to determine if the unknown species was related to one or more of four known species – A, B, C, D. The relationship between species can be determined by comparing the results of gel electrophoresis of the DNA from different species. The chart below represents the results of gel electrophoresis of the DNA from the unknown plant species and the four known species.
Which two known plant species is the unknown plant species most closely related to?
Answer:
Species C is the most closely related, followed by species D.
Explanation:
Gel electrophoresis technique is used to separate different fragments of DNI, RNA, and other macromolecules or proteins, concerning their size/weight and charge.
Gel electrophoresis of DNI lets us visualize how many different fragments of the molecule are present in a sample and how they differ from each other. The presence of fragments of the same size will be distinguished as a line named band. Each band represents many DNI fragments of similar size placed in the same position. The result of the gel electrophoresis will be different bands in different positions according to their sizes. The biggest ones will not migrate in the gel as much as the smallest ones.
In the exposed example we can assume that the most closely related species is C. The second most similar is species D.
The gel electrophoresis of the DNA from the unknown plant species resulted in five different bands, which means five types of fragments of different sizes.
- Four of the five bands expressed by the unknown species coincide with the bands of species C. Species C only lack one band to be exactly the same.
- Species D coincides in three bands and lack two bands to be exactly the same as the unknown species.
- Species A only coincides in one band.
- Species B does not coincide in any band, meaning that this is the most different one
For a better understanding, look at the attached files, where you will find the chart.
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Answer and Explanation:
a. The enes are responsible for expressing the characteristics of an individual. However, genes responsible for the same trait have different alleles, which make these traits different from each other, as is the case with chickpea flowers. Alleles can be h0m0zygous dominant (AA), recessive h0m0zygous (aa) or heterozygous (Aa), in short, dominant alleles are expressed in capital letters and are always expressed by the organism, so the alleles with greater proportions within an intersection, since they can be expressed in h0m0zygous and heterozygosis. Recessive alleles, however, can only be expressed in h0m0zygous and therefore have a smaller proportion.
B. Chickpeas have a type of dominance called incomplete dominance. This type of dominance occurs when the dominant alleles (AA) do not suppress the expression of the recessive genotype (aa), but joins the one showing an intermediate phenotype to the phenotype of the two alleles. This recessive phenotype can be seen in the heterozygous allele (Aa). Thus, we can see that the dominant flowers have AA alleles and have a white phenotype, while recessive flowers have aa alleles and have a blue phenotype, as explained in the question above. The crossing between these two plants generates an offspring where all the flowers present the pink phenotype, which is the intermediate phenotype between blue and white, in addition, this crossing generated an offspring that presents the Aa phenotype. You can also see this variety of colors at the crossing of the F2 generation, where most plants have the intermediate phenotype (Aa), followed by the dominant phenotype (AA) and followed by the recessive phenotype (aa). All crossings can be seen in attachments.
c. To test the hypothesis of one or more genes responsible for these characteristics, we would have to do biochemical and molecular tests. For that, it would be necessary to make a DNA extraction from the plant, PCR reactions and the isolation of one or more genes related to the color of the flowers.
