Question

Define aneuploidy. Name an allosomal hyperneuploidy condition and mention its characters.

Answer 1

Hint: Aneuploidy is a numerical change in a part of the chromosome set, whereas on other hand Polyploidy is defined as a numerical change in the whole set of chromosomes. Simply understand that Aneuploidy arises from errors in the chromosome segregation process , which can go wrong in many ways.

Complete answer:
As we discussed above, that the occurrence of one or more extra or missing chromosomes leads to an unbalance in chromosome complement, or any chromosome number which is not an exact multiple of the haploid number is called as Aneuploidy

An extra or missing chromosome is a common cause of many genetic disorders. Some of the cancerous cells also have abnormal numbers of chromosomes. Aneuploidy will originate during division of cells when the chromosomes do not separate properly between the two cells (nondisjunction). In most of the cases of aneuploidy in the germline result in miscarriage, Now lets understand , An allosome , which is a chromosome that differ from the rest of the chromosomes (autosomes) in its structure and size (X and Y chromosomes).

If we look at cases in hyper diploidy, where the number of chromosomes is higher than normal (46) which is caused due to disjunction at the time of meiosis which then results in trisomy, etc. of a chromosome.

On the other hand, in an allosomal hyperneuploid disorder, is an increase in the number of either the Y chromosome or X chromosome.

Let’s take example, in Klinefelter’s syndrome, where an extra X chromosome is present in the male. Some of the common characters in syndrome can include high-pitched voice, small-sized testicles, language and learning difficulties, infertility, gynecomastia, etc.

Additional information:
Keep in mind, the most common aneuploidy trisomy 21, which is found in Down syndrome, which affects 1 in 800 births. Also, Trisomy 18 (Edwards syndrome), and trisomy 13 leads to Patau syndrome.

Note: It’s important to know, Aneuploidy, which is the presence of an abnormal number of chromosomes inside a cell. For example, human cells have 45 or 47 chromosomes instead of the usual 46.But note that, it does not include differences of one or more complete sets of chromosomes.