Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Genetic engineering allows scientists to directly modify DNA sequences to create new, inheritable traits. One of the most widely used tools in modern biotechnology is CRISPR-Cas9, a system that can cut DNA at specific locations and insert, delete, or replace nucleotide sequences. This technology has dramatically accelerated the development of genetically modified organisms, including crop plants designed to withstand environmental stress. One real-world example is drought-resistant rice, engineered to survive longer periods without water by altering specific genes associated with water-use efficiency.
Traditional plant breeding can take many years and depends on naturally occurring genetic variation. In contrast, CRISPR enables scientists to introduce precise changes, such as enhancing the activity of genes involved in root development or reducing water loss through stomata. These changes modify the DNA sequence in plant cells. When these engineered cells are used to grow full plants, the new genetic trait becomes part of the plant’s chromosomes. The engineered plant can then pass these modified genes to its offspring, demonstrating a direct example of how genetic engineering creates inheritable genetic variation.
Diagram 1.
Source: https://openbiotechnologyjournal.com/VOLUME/16/ELOCATOR/e187407072205190/FULLTEXT/
One target gene for drought tolerance is OsDREB2A, a regulatory gene involved in stress-response pathways. CRISPR editing can increase this gene’s activity, allowing plants to maintain growth even when water is limited. Experiments comparing CRISPR-edited rice to non-edited varieties show clear differences in survival rates, biomass production, and grain yield under reduced-water conditions. These results provide measurable evidence of how specific DNA alterations can produce beneficial traits.
Diagram 2.
Source:
https://www.mdpi.com/2073-4425/12/6/912
Environmental pressures such as drought make this type of genetic variation particularly valuable. Climate change is increasing the frequency of extreme weather events, and crops with enhanced stress tolerance are becoming essential for maintaining global food supplies. Genetic engineering offers a way to introduce useful traits faster and more precisely than relying on natural mutation or recombination.
Table 1.
Water Availability (% of normal) | Average Biomass % Edited (g) | Average Biomass % Non-Edited (g) |
|---|---|---|
100 | 45 | 44 |
75 | 40 | 31 |
50 | 32 | 18 |
25 | 22 | 8 |
Graph of Information - Figure 1.
Table 2.
Water Availability (%) | Edited Yield (g/plant) | Non-Edited Yield (g/plant) |
|---|---|---|
100 | 30 | 29 |
75 | 25 | 18 |
50 | 18 | 9 |
25 | 10 | 3 |
Graph of Information - Figure 2.
Diagram 3.
Source: https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1232938/full
Using Table 1 and Figure 1, describe the mathematical relationship between water availability and biomass production in CRISPR-edited vs. non-edited rice.
According to the reading and Diagram 1, what does CRISPR-Cas9 do to DNA?
Using the reading and Diagram 2, explain how increasing activity of the OsDREB2A gene can lead to improved drought tolerance in rice plants.
Based on Diagram 3, which statement best describes how engineered DNA changes become heritable?
Using Table 2 and Figure 2, compare edited and non-edited rice yields under drought conditions. Include one numerical example.
Explain how CRISPR gene editing creates heritable genetic variation and how the data support its effects on drought tolerance in rice.
Claim:
Evidence:
Reasoning: