In the karyotype of a person with Down syndrome, or trisomy 21, an extra copy of chromosome 21 is apparent. This abnormality affects roughly 1 of every 700 children born and is the most common serious birth defect in the United States. People affected by Down syndrome often have mental retardation and shortened life spans.
Based on this scenario and your understanding of meiosis, what is the most likely basis for the extra chromosome in people with Down syndrome?

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The Answer of In the karyotype of a person with Down syndrome, or trisomy 21, an extra copy of chromosome 21 is apparent. This abnormality affects roughly 1 of every 700 children born and is the most common serious birth defect in the United States. People affected by Down syndrome often have mental retardation and shortened life spans.
Based on this scenario and your understanding of meiosis, what is the most likely basis for the extra chromosome in people with Down syndrome?

In the Karyotype of a Person with Down Syndrome, or Trisomy