The human genome contains approximately 10⁶ copies of an Alu sequence, one of the best-studied classes of short interspersed elements (SINEs), per haploid genome. Individual Alu units share a 282-nucleotide consensus sequence followed by a 3'-adenine-rich tail region [Schmid (1998)]. Given that there are approximately 3 x 10⁹ base pairs per human haploid genome, about how many base pairs are spaced between each Alu sequence?

Verified step by step guidance

Identify the total number of base pairs in the human haploid genome, which is given as approximately $3 \times 10^{9}$ base pairs.

Note the total number of Alu sequences per haploid genome, which is approximately \$10^{6}$ copies.

Understand that the problem asks for the average spacing between each Alu sequence, meaning the average number of base pairs between consecutive Alu elements.

Calculate the average spacing by dividing the total number of base pairs by the total number of Alu sequences using the formula: $\text{Average spacing} = \frac{\text{Total base pairs}}{\text{Number of Alu sequences}}$

Substitute the given values into the formula: $\text{Average spacing} = \frac{3 \times 10^{9}}{10^{6}}$ This will give the average number of base pairs between each Alu sequence.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Human Genome Size and Structure

The human haploid genome contains about 3 billion base pairs (3 x 10^9 bp). This total DNA length is organized into chromosomes and includes coding and non-coding regions. Understanding genome size is essential for calculating average distances between repeated sequences like Alu elements.

Alu Sequences and Short Interspersed Elements (SINEs)

Alu sequences are a type of SINE, approximately 282 base pairs long, repeated about one million times per haploid genome. These repetitive elements are dispersed throughout the genome and can be used as markers for genetic studies. Their abundance affects genome structure and spacing calculations.

Calculating Average Spacing Between Repetitive Elements

To find the average spacing between repetitive sequences, divide the total genome size by the number of repeats. This gives the average number of base pairs between each element, assuming even distribution. This concept helps estimate genomic distances between Alu sequences.

Recommended video:

Guided course

07:18

Discovery

Related Practice

Textbook Question

The following is a diagram of the general structure of the bacteriophage chromosome. Speculate on the mechanism by which it forms a closed ring upon infection of the host cell.

Textbook Question

How many base pairs are in a molecule of phage T2 DNA 52-µm long?

views

Textbook Question

Assume that a viral DNA molecule is a 50-µm-long circular strand with a uniform 20-Å diameter. If this molecule is contained in a viral head that is a 0.08-µm-diameter sphere, will the DNA molecule fit into the viral head, assuming complete flexibility of the molecule? Justify your answer mathematically.

Textbook Question

Mammals contain a diploid genome consisting of at least 10⁹ bp. If this amount of DNA is present as chromatin fibers, where each group of 200 bp of DNA is combined with 9 histones into a nucleosome and each group of 6 nucleosomes is combined into a solenoid, achieving a final packing ratio of 50, determine:

(a) the total number of nucleosomes in all fibers,

(b) the total number of histone molecules combined with DNA in the diploid genome, and