9 Questions
What is the karyotype of an individual with Down syndrome?
47, XX+ 21
Who was the British physician credited with describing Down syndrome in 1866?
John Langdon Down
What is the cause of Down syndrome?
Nondisjunction during meiosis
Which term describes the condition where there is only a single copy of a chromosome present?
Monosomy
What is the term for the incorrect separation of chromosomes or sister chromatids during meiosis?
Non-disjunction
In genetics, what is the term for the condition where there are three copies of a chromosome?
Trisomy
What term refers to the condition where there are 4 copies of chromosomes present?
Tetrasomy
Which term describes the normal condition of having complete two sets of chromosomes?
Euploidy
What is the term for the incorrect separation of chromosomes or sister chromatids during meiosis?
Non disjunction
Study Notes
Down Syndrome
- The karyotype of an individual with Down syndrome is 47, XY/+21 or 47, XX/+21.
- British physician John Langdon Down is credited with describing Down syndrome in 1866.
Chromosomal Conditions
- The cause of Down syndrome is having an extra copy of chromosome 21, resulting in three copies (trisomy).
- Nullisomy is the condition where there is only a single copy of a chromosome present.
- Non-disjunction is the term for the incorrect separation of chromosomes or sister chromatids during meiosis.
- Trisomy is the condition where there are three copies of a chromosome.
- Tetrasomy is the term for the condition where there are 4 copies of chromosomes present.
- Diploidy is the normal condition of having complete two sets of chromosomes.
Test your knowledge about Down syndrome, a genetic disorder caused by the presence of an extra chromosome 21. Learn about its characteristics and diagnosis, as well as the history and genetic basis of this condition.
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