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The Dp(16)1Yu model (also referred to as Dp(16)1Yey) contains a partial duplication of the mouse chromosome 16 (MMU16). Unlike the Ts65Dn model, Dp(16)1Yu contains a duplication of only the parts of chromosome 16 that are homologous to human chromosome 21. This makes the Dp(16)1Yu model a more genetically accurate representation of Down Syndrome.
The cause of the extra full or partial chromosome is still unknown. [92] Most of the time, Down syndrome is caused by a random mistake in cell division during early development of the fetus, but not inherited, [93] and there is no scientific research which shows that environmental factors or the parents' activities contribute to Down syndrome ...
Complete trisomy (having three copies of the entire chromosome) is lethal within days after conception. [13] Some partial deletions and partial duplications produce birth defects. The following diseases are some of those related to genes on chromosome 1 (which contains the most known genetic diseases of any human chromosome):
Unlike trisomy X, approximately half of women with tetrasomy X have no or incomplete pubertal development. Although in most cases tetrasomy X is significantly more severe than trisomy X, some cases of tetrasomy X are mild, and some cases of trisomy X severe. Like trisomy X, the full phenotypic range of tetrasomy X is unknown due to underdiagnosis.
[citation needed] These changes include an extra copy of part of chromosome 15 in each cell (partial trisomy 15) or a missing segment of the chromosome in each cell (partial monosomy 15). In some cases, several of the chromosome's DNA building blocks (nucleotides) are deleted or duplicated.
Turner syndrome (TS), also known as 45,X, or 45,X0, is a genetic disorder in which a person's cells have only one X chromosome or are partially missing an X chromosome (sex chromosome monosomy) leading to the complete or partial deletion of the pseudoautosomal regions (PAR1, PAR2) in the affected X chromosome.
There is considerable variability in the fraction of cells with trisomy 21, both as a whole and tissue-by-tissue. This is the cause of 1–2% of the observed Down syndromes. [4] There is evidence that mosaic Down syndrome may produce less developmental delay, on average, than full trisomy 21. [8]
Formally, the partial correlation between X and Y given a set of n controlling variables Z = {Z 1, Z 2, ..., Z n}, written ρ XY·Z, is the correlation between the residuals e X and e Y resulting from the linear regression of X with Z and of Y with Z, respectively.