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Zorluk: ZorGene Mutations and Chromosomal Aberrations

During DNA replication, exposure to an alkylating agent causes the insertion of a single extra nucleotide base into the coding region of a functional gene, while an error during spindle fiber assembly in meiosis causes two homologous chromosomes to fail to separate. Which of the following statements correctly distinguishes the molecular nature and scope of these two genetic events?

  1. The nucleotide insertion causes a frameshift gene mutation that alters the reading frame of a single protein, whereas non-disjunction causes a numerical chromosomal aberration altering total chromosome count.Cevap
  2. B
    The nucleotide insertion results in a chromosomal structural aberration, whereas non-disjunction leads exclusively to a point mutation within a single locus.
  3. C
    Both events alter the karyotype of the organism without affecting the amino acid sequence of synthesized polypeptides.
  4. D
    The insertion leads to polyploidy across all autosomes, whereas non-disjunction alters only the nucleotide sequence of the nitrogenous bases.

Cevap

The nucleotide insertion causes a frameshift gene mutation that alters the reading frame of a single protein, whereas non-disjunction causes a numerical chromosomal aberration altering total chromosome count.
A single nucleotide addition within a gene alters the codon triplet reading frame (frameshift mutation), affecting only that specific gene product. In contrast, non-disjunction involves the failure of chromosome separation, leading to aneuploidy, which is a numerical chromosomal aberration.

Adım Adım Çözüm

1
Classify the single nucleotide insertion event.
Insertion of a single base into a gene's coding sequence alters the triplet codon reading frame during translation (frameshift gene mutation).
Gene mutations involve chemical or sequence changes within localized nucleotides of a single gene.
2
Classify the homologous chromosome non-separation event during meiosis.
Failure of homologous chromosomes to separate is termed non-disjunction, resulting in gametes with extra or missing whole chromosomes (aneuploidy).
Non-disjunction affects macro-structures (whole chromosomes), making it a numerical chromosomal aberration.
3
Compare the scope and classification of both events.
The insertion is a gene-level mutation affecting one polypeptide, while non-disjunction is a chromosomal aberration affecting total chromosome number.
Gene mutations affect nucleotide sequences, whereas chromosomal aberrations affect gross chromosome structure or number.

Anahtar Kavram

Distinction between Gene Mutations and Chromosomal Aberrations
Tahmini Süre:1m 30s
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Konular

Gene Mutations and Chromosomal Aberrations

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