mutation that removes dna crossword

Neter

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22-11-2024

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Mutation That Removes DNA: A Crossword Clue and Scientific Exploration

This article delves into the world of genetic mutations, specifically focusing on the type of mutation that removes DNA – a common crossword clue. We will explore the scientific mechanisms behind these deletions, their consequences, and their significance in various biological contexts.

What is a Deletion Mutation?

A deletion mutation is a type of genetic mutation characterized by the loss of one or more nucleotides (the building blocks of DNA) from a DNA sequence. These deletions can range in size, from a single base pair to large segments of a chromosome. The impact depends heavily on the size and location of the deleted sequence.

Mechanisms of Deletion Mutations

Several mechanisms can lead to DNA deletions. These include:

• Unequal crossing over: During meiosis (cell division that produces gametes), homologous chromosomes can misalign, leading to unequal exchange of genetic material. One chromosome ends up with a duplication, while the other experiences a deletion.
• DNA replication errors: Mistakes during DNA replication can result in the omission of segments of DNA. These errors can be caused by various factors, including DNA damage or the action of certain enzymes.
• Excision repair: A cellular repair mechanism meant to correct DNA damage sometimes accidentally removes more genetic material than intended, leading to a deletion.
• Chromosomal breakage: Physical damage to a chromosome, possibly induced by radiation or certain chemicals, can lead to large-scale deletions. Broken pieces may be lost during repair, resulting in the loss of genes.

Consequences of Deletion Mutations

The effects of deletion mutations vary greatly. Small deletions might have minimal impact, especially if they occur in non-coding regions of DNA (regions that don't code for proteins). Larger deletions, or deletions within coding regions, can have more severe consequences:

• Frameshift mutations: If the deletion is not a multiple of three nucleotides, it shifts the reading frame of the gene. This leads to a completely altered amino acid sequence downstream of the deletion, often resulting in a non-functional protein.
• Loss of gene function: Deletions removing entire genes can result in the complete loss of the protein product, leading to a variety of phenotypes depending on the gene's role. This can range from subtle changes to severe developmental abnormalities or diseases.
• Chromosomal instability: Large deletions can make the chromosome more prone to breakage, leading to further genomic instability.

Examples and Significance

Deletion mutations are implicated in numerous human genetic diseases, including:

• Cri-du-chat syndrome: Caused by a deletion on chromosome 5, characterized by a distinctive cry in infants and intellectual disability.
• Williams-Beuren syndrome: Results from a deletion on chromosome 7, leading to distinctive facial features, cardiovascular problems, and developmental delays.
• Duchenne muscular dystrophy: Often caused by deletions within the dystrophin gene.

Beyond human diseases, deletion mutations play a role in evolution. They can contribute to genetic diversity and, in some cases, drive the development of new traits.

Deletion Mutations: A Crossword Clue Solved

So, the answer to the crossword clue "Mutation that removes DNA" is DELETION. Understanding the underlying mechanisms and consequences of this type of mutation is crucial for appreciating its broad implications in genetics, medicine, and evolutionary biology. The scientific understanding of these mutations continues to grow, providing valuable insight into disease mechanisms and genetic variation.