Question

An individual's unique set of _________ can be used in DNA profiling. a. DNA sequences b. short tandem repeats c. SNPs d. all of the above

Short answer

The correct answer is 'd. all of the above'.

Step-by-step solution

Understanding DNA Profiling

DNA profiling is a technique used to identify individuals based on their unique DNA characteristics. This involves looking at various DNA features that can vary greatly from person to person.

Define Each Option

Option a, 'DNA sequences', refers to the entire set of nucleotides in a DNA molecule. Option b, 'short tandem repeats', are patterns in the DNA that are repeated and are used in profiling due to their high variability. Option c, 'SNPs' (Single Nucleotide Polymorphisms), represent variations at a single nucleotide position in the genome.

Evaluating Each Option

DNA sequences contain all genetic information, but using the entire sequence can be complex for profiling. Short tandem repeats (STRs) are highly variable among individuals, making them ideal for profiling. SNPs are single base pair variations that are also considered in more advanced profiling techniques.

Selecting the Best Fit

In practice, STRs are most commonly used due to their high variability and ease of analysis. However, comprehensive DNA profiling can use sequences, STRs, and SNPs together. Thus, all the provided options can contribute to creating a DNA profile.

Final Decision

Taking into consideration that DNA profiles can involve overall sequencing as well as specific, variable parts like STRs and SNPs, the most complete answer is 'all of the above'.

Key concepts

DNA Sequences

DNA sequences are the unique arrangements of nucleotides (adenine, cytosine, guanine, and thymine) that make up your DNA. Think of them like a complex cookbook, where each sequence holds instructions for building and maintaining your body. A full DNA sequence tells the story of your entire genetic makeup.
Understanding DNA sequences is crucial because they contain the code for everything from your hair color to your susceptibility to certain diseases. However, analyzing complete DNA sequences for profiling purposes can be a daunting task due to their length and complexity. Scientists use sophisticated techniques to read these sequences, which involves mapping out the billions of base pairs. This process, called sequencing, is vital for many areas of genetics, including research, medical diagnostics, and DNA profiling.
In DNA profiling, while entire DNA sequences provide comprehensive genetic information, they are not often used directly due to their complexity and the vast amount of data involved. Instead, specific regions like STRs and SNPs are more targeted because they hold variations that differ between individuals.

Short Tandem Repeats (STRs)

STRs, or Short Tandem Repeats, are short sequences of DNA that are repeated sequentially. These repeats are found at various locations in the genome and are highly variable among individuals, which makes them extraordinarily useful for DNA profiling.
Imagine STRs as a sentence where a word is repeated several times, like 'run run run'. Each person might have a different number of repeats, which provides a unique pattern for identification. The variability in the number of repeats allows STRs to act like a unique barcode for each person's DNA. This is why they are a staple in forensic science and legal cases to match suspects or identify remains.
To perform DNA profiling with STRs, scientists collect samples and use a process called polymerase chain reaction (PCR) to make many copies of these regions. This amplification process makes it easier to analyze and determine the specific pattern of STRs, helping to identify individuals accurately. Their high degree of polymorphism makes STRs the preferred method for DNA profiling.

Single Nucleotide Polymorphisms (SNPs)

Single Nucleotide Polymorphisms, or SNPs, are the most common type of genetic variation among people. Each SNP represents a difference in a single DNA building block, called a nucleotide. For example, one person might have an adenine (A) in a particular spot, whereas another person might have a cytosine (C).
SNPs occur throughout a person's DNA, roughly one every 1,000 nucleotides, which means there are several million SNPs in a person's genome. This makes them very useful for studying genetic variations across individuals. While they are less variable than STRs, the sheer volume of SNPs presents a comprehensive picture when used in DNA profiling.
In terms of application, SNPs are often used in genetic association studies that connect them to various diseases and conditions. This information can be pivotal for personalized medicine, allowing treatments tailored to an individual's genetic makeup.
Besides medical applications, SNPs contribute significantly to ancestry testing and provide insights into human evolutionary history. Their ability to pinpoint variations at single positions in the genome makes them a powerful tool in the arsenal of genetic analysis.