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Chromosome pairs

Review your understanding of chromosome pairs in this free article aligned to NGSS standards.

Key points:

  • 365体育网投 species has its own specific number of chromosomes. For example, humans have 46 chromosomes in a typical body cell.
  • Many species have chromosomes that come in matched pairs. For example, the 46 chromosomes in a human cell can be organized into 23 pairs.
  • These paired chromosomes are called homologous chromosomes. Homologous chromosomes are the same size and shape.
  • Homologous chromosomes contain the same genes. However, they may have different alleles, or versions, of those genes.
  • Scientists and medical professionals can use a karyotype to view an organism¡¯s sets of chromosomes. In a karyotype, pairs of homologous chromosomes are arranged next to each other. This makes it easier to see if there are any differences between chromosomes that may lead to a genetic condition.
A human karyotype. Image credit: ¡°Karyotype from a female human lymphocyte (46, XX)" by Andreas Bolzer, Gregor Kreth, Irina Solovei, Daniela Koehler, Kaan Saracoglu, Christine Fauth, Stefan M¨¹ller, Roland Eils, Christoph Cremer, Michael R. Speicher, Thomas Cremer, CC BY 2.5.

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