Problem 4 - Campbell Biology

Question

A paleontologist has recovered a bit of tissue from the 400 -yearold preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from a sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing? (A) SNP analysis (B) polymerase chain reaction (PCR) (C) electroporation (D) gel electrophoresis

Step-by-Step Solution

Answer

B) PCR

Step 1: Understand the Problem

To solve this problem, it is essential to determine which technique is best suited for increasing the amount of dodo DNA for testing.

Step 2: Analyze the Techniques

Review each option to understand what it does:(A) SNP analysis: This technique involves identifying variations at single nucleotide positions. It does not amplify DNA.(B) Polymerase chain reaction (PCR): This technique is used to amplify specific segments of DNA, making many copies of a particular region.(C) Electroporation: This technique introduces DNA into cells using an electric field, but it does not amplify DNA.(D) Gel electrophoresis: This technique is used to separate DNA fragments by size but does not amplify DNA.

Step 3: Identify the Best Technique

To increase the amount of dodo DNA for testing, the technique must be able to make many copies of the DNA. PCR (polymerase chain reaction) is specifically designed to amplify DNA.

Step 4: Conclusion

Given the need to increase the amount of DNA, the most appropriate technique is PCR (polymerase chain reaction).

Key Concepts

polymerase chain reaction (PCR)

Polymerase Chain Reaction (PCR) is a revolutionary technique in molecular biology that allows scientists to amplify specific segments of DNA. Developed by Kary Mullis in 1983, PCR has become an essential tool in research labs.

The PCR process involves a few key steps:

• Denaturation: Heating the DNA sample to separate the double-stranded DNA into two single strands.


• Annealing: Cooling the sample to allow primers (short DNA sequences) to attach to the target DNA region.


• Extension: Using a DNA polymerase enzyme, new DNA strands are synthesized by adding nucleotides to the primers.

These steps are repeated for 20-40 cycles, leading to exponential amplification of the target DNA region.

PCR plays a crucial role in various fields including medicine, forensic science, and genetics. In paleontology, it helps in analyzing ancient DNA samples, such as the one from the 400-year-old dodo tissue mentioned in the exercise. By amplifying the DNA, researchers can obtain enough genetic material for further analysis and comparison.

DNA testing methods

DNA testing methods encompass a wide array of techniques used to analyze genetic material. These methods are essential for applications in areas like forensic science, medical diagnostics, and historical studies.

Here are a few common DNA testing methods:

• Restriction Fragment Length Polymorphism (RFLP): Analyzes the length of DNA fragments cut by specific enzymes.


• Short Tandem Repeat (STR) analysis: Examines repeating units in DNA sequences, widely used in forensic science.


• Single Nucleotide Polymorphism (SNP) analysis: Involves identifying variations at single nucleotide positions.

Each method has its unique applications and benefits. PCR, mentioned earlier, often plays a supportive role in these methods by providing sufficient quantities of DNA for analysis.

DNA testing is also invaluable in evolutionary studies. By comparing DNA sequences from extinct and extant species, scientists can gain insights into evolutionary relationships and processes.

DNA analysis in paleontology

DNA analysis in paleontology is a fascinating field that provides insights into the genetic makeup of extinct species. By extracting and analyzing ancient DNA (aDNA) from preserved specimens, scientists can unravel the evolutionary history and biology of long-gone organisms.

In the context of the dodo tissue from the exercise, DNA analysis can be instrumental in understanding the evolutionary connections of the dodo with living birds. This involves several steps:

• Sample Extraction: Obtaining DNA from fossilized or preserved remains.


• DNA Amplification: Using techniques like PCR to make multiple copies of the extracted DNA.


• Sequencing: Determining the exact sequence of nucleotides in the DNA.


• Comparative Analysis: Comparing the ancient DNA sequence with those of living species to draw evolutionary inferences.

One challenge in DNA analysis in paleontology is the degradation of DNA over time. However, advancements in technology are continually improving our ability to work with ancient DNA. Through these methods, we continue to piece together the evolutionary puzzle of life on Earth.