I believe he is looking for an allele
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosomes. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
<span>DiGeorge syndrome is a result of a deletion on the 22nd chromosome. A mutation causes a loss of a part of the chromosome and there is part of chromosome 22 is missing.
</span>47,XXY karyotype, known as Klinefelter’s syndrome <span>results in males with three sex chromosomes. This may occur as a result of sex chromosomes not being separated in meiosis of both of the mother or the father of the diseased.
Fragile X syndrome is a result of the expansion of trinucleotide repeats. This means that a sequence of three nucleotides is uncontrollably multiplying in the X chromosome sequence, causing various health problems and deformities.
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I think it is Binary fission