Quick Answer: What is Trisomy Class 12?

Listen to pronunciation. (TRY-soh-mee) The presence of an extra chromosome in some or all of the body’s cells. This results in a total of three copies of that chromosome instead of the normal two copies.

What is trisomy in biology class 12?

Hint: Trisomy refers to a genetic condition in which a person has three copies of chromosome instead of two copies of Chromosome.

What is trisomy give an example class 12?

The term “trisomy” is used to describe the presence of an extra chromosome — or three instead of the usual pair. For example, trisomy 21 or Down syndrome occurs when a baby is born with three #21 chromosomes. In trisomy 18, there are three copies of chromosome #18 in every cell of the body, rather than the usual pair.

What is trisomy short answer?

A trisomy is a chromosomal condition characterised by an additional chromosome. A person with a trisomy has 47 chromosomes instead of 46. Down syndrome, Edward syndrome and Patau syndrome are the most common forms of trisomy.

What is trisomy in plants?

A trisomy is atype of aneuploidy (an abnormal number of chromosome) The no of possible trisomics in an organisms will be equal to its haploid chromosome number. In plants , the first case of trisomy was investigated in jimson weed(Datura stramonium 2n=24 ) by A.F. Blakeslee and J. Belling in 1924.

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What means of trisomy?

(TRY-soh-mee) The presence of an extra chromosome in some or all of the body’s cells. This results in a total of three copies of that chromosome instead of the normal two copies. For example, Down syndrome (trisomy 21) is caused by having three copies of chromosome 21 instead of the usual two copies.

What is trisomy and when does it occur?

The term trisomy describes the presence of three chromosomes instead of the usual pair of chromosomes. For example, trisomy 21, or Down syndrome, occurs when a baby has three #21 chromosomes. Other examples are trisomy 18 and trisomy 13, fatal genetic birth disorders.

What is trisomy by Brainly?

Trisomy. … Trisomy is when a diploid organism has three copies of one of its chromosomes instead of two. Trisomy is an example of aneuploidy, or an organism having an abnormal number of chromosomes. Niccherip5 and 18 more users found this answer helpful.

What is trisomy formula?

Terminology. The number of chromosomes in the cell where trisomy occurs is represented as, for example, 2n+1 if one chromosome shows trisomy, 2n+1+1 if two show trisomy, etc. “Full trisomy”, also called “primary trisomy”, means that an entire extra chromosome has been copied.

Why does a trisomy occur?

Trisomy is the presence of an extra chromosome. This can arise as a result of non-disjunction, when homologous chromosomes fail to separate at meiosis resulting in a germ cell containing 24 chromosomes rather than 23. Trisomy of any chromosome can occur, but all except trisomies 21, 18, 13, X and Y are lethal in utero.

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What is Trisomy 9 called?

Mosaic trisomy 9 is a rare chromosomal disorder in which the entire 9th chromosome appears three times (trisomy) rather than twice in some cells of the body. The term “mosaic” indicates that some cells contain the extra chromosome 9, while others have the typical chromosomal pair.

What is Nondisjunction?


Nondisjunction means that a pair of homologous chromosomes has failed to separate or segregate at anaphase so that both chromosomes of the pair pass to the same daughter cell. This probably occurs most commonly in meiosis, but it may occur in mitosis to produce a mosaic individual.

What is trisomy 21 risk?

Down syndrome (trisomy 21) is the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age. All forms of prenatal testing for Down syndrome must be voluntary.

What is Autotetraploid?

Definition of autotetraploid

: an individual or strain whose chromosome complement consists of four copies of a single genome due to doubling of an ancestral chromosome complement.

What is the karyotype?

A karyotype is an individual’s collection of chromosomes. The term also refers to a laboratory technique that produces an image of an individual’s chromosomes. The karyotype is used to look for abnormal numbers or structures of chromosomes.

What is balanced tertiary Trisomics?

Balanced tertiary trisomics are tertiary trisomics constituted in such a way that the dominant allele of a marker gene closely linked with the interchange breakpoint is carried on the tertiary chromosome. • The recessive allele is carried on each of the two normal chromosomes.

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