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Chromosome 12

Chromosome 12

deletion of the proximal short arm of chromosome 12 is rare and occurs de novo. Microcephaly, narrow forehead, pointed nose and micrognathia are present. Mental and growth retardation are significant but inner organ malformations are generally not present. 12p trisomy nearly always results from a familial translocation. The phenotype includes turricephaly with flat apex, high bulging forehead, flat rectangular face, pronounced hypertelorism, a very short nose with a broad and poorly defined bridge, a short neck with cutaneous folds, ear abnormalities, hypotonia, severe growth and mental retardation and signs of precocious aging in adolescents. Tetrasomy 12p is consistent with pallister-killian syndrome. The critical region appears to be confined to 12p11.2.

12q2 trisomy is uncommon and results most frequently from malsegregation of a parental translocation. The patients show a relatively large head with frontal bossing, rectangular face with chubby cheeks and short limbs, especially in the proximal segment. Mental retardation is severe and 62b growth retardation variable. Among others, genes for lactate dehydrogenase B, phenylalanine hydroxylase and haemolytic anaemia due to glyceraldehyde -3-phosphate dehydrogenase deficiency are assigned to chromosome 12.


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Re: Mitochondrial DNA

There are genetic diseases caused by defects carried on the mitochondrial chromosome that can have clear phenotypic consequences. http://www.umdf.org/site/c.8qKOJ0MvF7LUG/b.7934627/k.3711/What_is_Mitochondrial_Disease.htm

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by jonmoulton
Mon Sep 08, 2014 5:23 pm
 
Forum: Genetics
Topic: Mitochondrial DNA
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Views: 692

Colorblindness Probability Help!

The incidence of an XXY karyotype is about 1 in every 1000 male births, the extra X chromosome coming either from the mother's egg or the father's sperm by nondisjunction during meiosis. Suppose the baby's father has red-green colorblindness. Would you predict that ...

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by kaylagh
Sun Sep 07, 2014 6:07 am
 
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Chromatin

I am all for skipping the mitochondrial chromosome for now:) Thank you for your explanation...it really helps:)

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by Hannamerika
Thu Sep 04, 2014 10:13 pm
 
Forum: Genetics
Topic: Chromatin
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Re: Chromatin

Before replication there were 23 pairs of molecules, 23 of maternal origin and 23 of paternal origin, plus the maternally-contributed mitochondrial chromosome (which I'll ignore for the rest of this post). Counting chromosomal centromeres, there are 46 centromeres total. After replication there ...

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by jonmoulton
Thu Sep 04, 2014 3:04 pm
 
Forum: Genetics
Topic: Chromatin
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Chromatin

... cell for it to replicate. Is that correct? That way once the chromatin replicates and does all of it's twisting and coiling, we then have our 23 chromosome pairs. Yes?

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by Hannamerika
Thu Sep 04, 2014 9:12 am
 
Forum: Genetics
Topic: Chromatin
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