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Sex cells have either one X or one Y chromosome. Male offspring have XY and female offspring have XX. In the case of two X's, one is inactivated. This a random act in the cells' early development.
It can be seen easily in cats as their coat color genes are found on the X chromosome. In female cats, one X may have the gene for black and the other may have the gene for red. When this is expressed, a mixture of red and black is seen. This color pattern is called a tortoiseshell. These cats are almost always female.
The male will be either black or red. The colors can also be dilute (blue and cream) with the same pattern. Males that have an extra X chromosome can show the same pattern as females.
Wiki User
∙ 9y ago
Wiki User
∙ 8y agoHuman females (and other animals) have two X chromosomes. Only one is active, the other is inactivated. It can be seen in the cell as something called a Barr Body.
Cats have coat color genes on the X chromosomes. Males have only one X and they will have only one hair color. The white pattern and striping are on other chromosomes.
But females have the two X's. The inactivation of one X is random. You can see this in a cat that is a toritishell. Each hair cell will have one hair that is either red or black.
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What is the x chromosome inactivation?
this is the process by which one of the two copies of the X-chromosomes present in female animals is inactivated
Which term describes something that happens in female mammals?
X chromosome inactivation happens in female mammals.
How many chromosomes do you have in a cell found in your elbow?
The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The X chromosome spans about 155 million DNA building blocks (base pairs) and represents approximately 5 percent of the total DNA in cells. Each person normally has one pair of sex chromosomes in each cell. Females have two X chromosomes, while males have one X and one Y chromosome. Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in cells other than egg cells. This phenomenon is called X-inactivation or Lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells. Some genes on the X chromosome escape X-inactivation. Many of these genes are located at the ends of each arm of the X chromosome in areas known as the pseudoautosomal regions. Although many genes are unique to the X chromosome, genes in the pseudoautosomal regions are present on both sex chromosomes. As a result, men and women each have two functional copies of these genes. Many genes in the pseudoautosomal regions are essential for normal development. Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. The X chromosome likely contains between 900 and 1,400 genes. These genes perform a variety of different roles in the body. (Note: So I believe your answer will be 46; 23x2)
Is there an X or Y chromosome in an egg?
An egg will have the X chromosome and the sperm will have an X or Y chromosome.
Why don't males have Barr bodies?
Both Male and Female have the barr body, but in different chromosones. The above statement is INCORRECT. Barr bodies are formed mainly in females due to females having two X chromosomes while males normally have only one X chromosome (and a Y chromosome). The Barr body is formed from the inactive X chromosome. Males can sometimes be born with a mutation of having too many X chromosomes, in which case Barr Bodies would also be found in those specific males which typically causes Klinefelter's Syndrome.
What is x chromosome inactivation in human system?
its not inactive
Occurs when one x-chromosomes is randomly turned off and forms a barr body?
An X-inactivation occurs when one X-chromosome is randomly turned off and forms a Barr body. It is also known as lyonization.
What accounts for the mosaic color pattern of a female calico cat?
X chromosome inactivation
What is the x chromosome inactivation?
this is the process by which one of the two copies of the X-chromosomes present in female animals is inactivated
Which term describes something that happens in female mammals?
X chromosome inactivation happens in female mammals.
Why does x inactivation occurs in female not in male?
Male carry XY genotype whereas female has XX. Two copies of X chromosome means, there is a great chance of potentially toxic double dose of X-linked genes. It is known that 1000s of genes responsible for growth and cell viability are there in X chromosomes.To avoid the over production of these genes in female (where 2 X chromosomes present), there is a mechanism evolved that transcriptionally control or silence on of these two X chromosome.http://www.nature.com/scitable/topicpage/x-chromosome-x-inactivation-323
How many chromosomes do you have in a cell found in your elbow?
The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The X chromosome spans about 155 million DNA building blocks (base pairs) and represents approximately 5 percent of the total DNA in cells. Each person normally has one pair of sex chromosomes in each cell. Females have two X chromosomes, while males have one X and one Y chromosome. Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in cells other than egg cells. This phenomenon is called X-inactivation or Lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells. Some genes on the X chromosome escape X-inactivation. Many of these genes are located at the ends of each arm of the X chromosome in areas known as the pseudoautosomal regions. Although many genes are unique to the X chromosome, genes in the pseudoautosomal regions are present on both sex chromosomes. As a result, men and women each have two functional copies of these genes. Many genes in the pseudoautosomal regions are essential for normal development. Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. The X chromosome likely contains between 900 and 1,400 genes. These genes perform a variety of different roles in the body. (Note: So I believe your answer will be 46; 23x2)
How might x inactivation cause patchy hairiness on women who have congenital generalized hypertrichosis even though the disease causing allele is dominant?
Since one X chromosome in each cell is randomly inactivated at some point during development, a woman heterozygous for hypertrichosis would have varying regions of patchy hair if the alleles responsible for the trait were located on the X chromosome. Variation would look similar to the varied tortoise shell coat color pattern on female cats, where the presence of yellow and black (red and gold/blue and cream) is controlled by X chromosome inactivation.
Is Barr body present in female with Down syndrome?
Yes, a female with Down syndrome has three copies of chromosome 21, but only two copies of the X chromosome. Regarding sex chromosomes, she is genetically normal. For this reason X chromosome inactivation would occur, and she would have one Barr body per cell.
What is the difference between x-inactivation and genomic imprinting?
The difference between them is that : In genomic imprinting : one of the alleles in the two chromosomes ( for example the color of the eyes ) are tend to be heavily methylated, in contrast to the nonimpringting copy of the allele which typically is not methylated. In X-chromosome in activation : As you know in female there are two X chromosomes, so one of the two X xhromosomes is methylated which mean one of the two chromosomes become inactivation.
What is x linked inheritance diseases?
X-linked genes are found on the sex X chromosome. X-linked genes just like autosomal genes have both dominant and recessive types. Recessive X-linked disorders are rarely seen in females and usually only affect males. This is because males inherit their X chromosome and all X-linked genes will be inherited from the maternal side. Fathers only pass on their Y chromosome to their sons, so no X-linked traits will be inherited from father to son. Females express X-linked disorders when they are homozygous for the disorder and become carriers when they are heterozygous. An infamous recessive X-linked disorder is Hemophilia A. Hemophilia is a disorder where blood does not clot properly due to a shortage of clotting factor VIII. This disorder gained recognition as it traveled through royal families, notably the descendent's of Britain's Queen Victoria. X-linked dominant inheritance will show the same phenotype as a heterozygote and homozygote. Just like X-linked inheritance, there will be a lack of male-to-male inheritance, which makes it distinguishable from autosomal traits. One example of a X-linked trait is Coffin-Lowry syndrome, which is caused by a mutation in ribosomal protein gene. This mutation results in skeletal, craniofacial abnormalities, mental retardation, and short stature. X chromosomes in females undergo a process known as X inactivation. X inactivation is when one of the two X chromosomes in females is almost completely inactivated. It is important that this process occurs otherwise a woman would produce twice the amount of normal X chromosome proteins. The mechanism for X inactivation will occur during the embryonic stage. For people with disorders like trisomy X, where the genotype has three X chromosomes, X-inactivation will inactivate all X chromosomes until there is only one X chromosome active. X inactivation is not only limited to females, males with Klinefelter syndrome, who have an extra X chromosome, will also undergo X inactivation to have only one completely active X chromosome.
Is an x chromosome and chromosome the same thing?
An x chromosome is specifically a feminine chromosome. With a x and y chromosome its male, with a x and x, it is a female.
