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Which genes are expressed even when present on only one chromosome?
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Why do males and females express X-linked alleles differently?
X-linked recessive traits that are not related to feminine body characteristics are primarily expressed in the observable characteristics, or phenotype of men. This is due to the fact that men only have one X chromosome. Subsequently, genes on that chromosome not coding for gender are usually expressed in the male phenotype even if they are recessive since there are no corresponding genes on the Y chromosome in most cases. In women, a recessive allele on one X chromosome is often masked in their phenotype by a dominant normal allele on the other. This explains why women are frequently carriers of X-linked traits but more rarely have them expressed in their own phenotypes.
How can two species have the same chromosome number yet have very different attributes?
See, The difference in two species comes from there genetic code (genes) and not from the number of chromosomes present in their cell.. So even if two species have same number of chromosomes BUT different genetic code then they ARE LIKELY TO BE DIFFERENT!! hope you have got your answer..:)
Is it possible for a female to inherit a sex linked trait?
Males carry one sex-linked trait. Females, carry most of the rest. Sex-linked traits, other than gender, are almost exclusively associated with the X chromosome. That is why it is sometimes said that sex-linked traits are carried by females, but that is not exactly right. It is not as simple as that, so read on. Short Explanation: There are just over a thousand genes on the X chromosome and about 26 on the Y. Of the 26 on the Y, 9 relate to sperm and one (SRY) relates to male anatomy, the others involved in general tasks. Just the fact that there are almost a hundred times more genes on the X chromosome means that traits related to the X, and variations in those traits, are far far more common. In fact, it is even more exclusive to the X than numbers suggest. Sex-linked traits are those that can only be passed along from the father and not the mother or from the mother and not the father. Obviously, males do carry and pass on sex-linked traits, just not very many. Gender can only be passed along from the father, along with genes related to sperm. Females pass on to the male offspring a larger number of traits, (such as some color blindness and male pattern baldness) which have no counterpart in the Y chromosome. More: Males have an X and a Y chromosome and females have two X chromosomes. Because the Y chromosome is smaller than the X with far fewer genes, there are genes carried only on the X and only gotten from the mother. That does not mean that all males have Y chromosomes that are the same. Overwhelmingly though, the absence of the set of genes on the Y chromosome results in the corresponding genes on the X chromosome being expressed, in particular all of the X-linked disorders of a gene of an X chromosome in a male do not have a second X gene that can be expressed to compensate. Thus, there are a set of sex-linked traits that can only come from the mother. (Color blindness and male pattern baldness are the two most discussed examples.) A male offspring (son) has the same Y chromosome as the father and hence any traits influenced by that chromosome. A female offspring (daughter) has the same X chromosome as the father and hence any traits influenced by that chromosome. A recessive gene on the X from the father will not usually be expressed in a daughter, but a dominant gene on the X from the father will be expressed in the daughter. For a female to inherit a trait associated with an X-chromosome recessive gene, there must be two copies, one from each parent. Aside: The issue of gender-connected inherited traits has much more complexity than this simple discussion can address. For example, not all of the so-called male characteristics are carried on the male (Y) chromosome. The expression of genes on other chromosomes, from both the mother and father, is influenced by genes on the Y chromosome or simply by the absence of two X chromosomes. The reader should investigate further. Caveat: This discussion applies to humans and other mammals with the XX/XY sex determination system. See related links. Fun Fact: A woman discovered that the Y chromosome was male. While studying worms, in 1905, Nettie Stevens at Bryn Mawr College identified the Y chromosome as the determining factor in gender.
One of the main reasons genes assort independent of one another is that?
Genes on different chromosomes assort independently of each other by dint of the fact that they are on different chromosomes. The closer a gene is to another on the same chromosome the more likely they are to remain together even with crossing over.
What is an allele whose trait always shows up in the organism?
type 2 Diabetes
What genes are expressed even when present on only one chromosome?
dominant genes
A chromosome is made up of even smaller bodies?
It is made up of genes.
If a chromosome is highly methylated?
The gene is not expressed, even if it is a normal gene in every other way.
Why do males and females express X-linked alleles differently?
X-linked recessive traits that are not related to feminine body characteristics are primarily expressed in the observable characteristics, or phenotype of men. This is due to the fact that men only have one X chromosome. Subsequently, genes on that chromosome not coding for gender are usually expressed in the male phenotype even if they are recessive since there are no corresponding genes on the Y chromosome in most cases. In women, a recessive allele on one X chromosome is often masked in their phenotype by a dominant normal allele on the other. This explains why women are frequently carriers of X-linked traits but more rarely have them expressed in their own phenotypes.
What is the extract of RNA?
RNA is the expressed form of a gene (which is DNA encoded). By isolating RNA, it is possible to determine which genes were being expressed and to what relative (or even absolute) level.
Which allele is expressed even if only one copy is present in genotype?
dominant alleles
Why are x linked alleles expressed in males even if they are recessive?
X-linked are not recessive nor dominant. X-linked just do not show. On the sex-linked chromosomes the Y chromosome of the X-Y pair dominates the trait whether its recessive or dominant!Actually, all x-linked alleles are expressed because males only have one x-chromosome, so whatever is there, dominant or recessive, is expressed.
Does a gene contain hundreds of chromosomes?
No, it's the other way round a chromosome conatins many genes. On humans one can contain anywhere between hundreds or thousands of genes, some are longer than others . A map of the human genome lives here: http://www.ncbi.nlm.nih.gov/mapview/map_search.cgi?taxid=9606
How can two species have the same chromosome number yet have very different attributes?
See, The difference in two species comes from there genetic code (genes) and not from the number of chromosomes present in their cell.. So even if two species have same number of chromosomes BUT different genetic code then they ARE LIKELY TO BE DIFFERENT!! hope you have got your answer..:)
Is it possible for a female to inherit a sex linked trait?
Males carry one sex-linked trait. Females, carry most of the rest. Sex-linked traits, other than gender, are almost exclusively associated with the X chromosome. That is why it is sometimes said that sex-linked traits are carried by females, but that is not exactly right. It is not as simple as that, so read on. Short Explanation: There are just over a thousand genes on the X chromosome and about 26 on the Y. Of the 26 on the Y, 9 relate to sperm and one (SRY) relates to male anatomy, the others involved in general tasks. Just the fact that there are almost a hundred times more genes on the X chromosome means that traits related to the X, and variations in those traits, are far far more common. In fact, it is even more exclusive to the X than numbers suggest. Sex-linked traits are those that can only be passed along from the father and not the mother or from the mother and not the father. Obviously, males do carry and pass on sex-linked traits, just not very many. Gender can only be passed along from the father, along with genes related to sperm. Females pass on to the male offspring a larger number of traits, (such as some color blindness and male pattern baldness) which have no counterpart in the Y chromosome. More: Males have an X and a Y chromosome and females have two X chromosomes. Because the Y chromosome is smaller than the X with far fewer genes, there are genes carried only on the X and only gotten from the mother. That does not mean that all males have Y chromosomes that are the same. Overwhelmingly though, the absence of the set of genes on the Y chromosome results in the corresponding genes on the X chromosome being expressed, in particular all of the X-linked disorders of a gene of an X chromosome in a male do not have a second X gene that can be expressed to compensate. Thus, there are a set of sex-linked traits that can only come from the mother. (Color blindness and male pattern baldness are the two most discussed examples.) A male offspring (son) has the same Y chromosome as the father and hence any traits influenced by that chromosome. A female offspring (daughter) has the same X chromosome as the father and hence any traits influenced by that chromosome. A recessive gene on the X from the father will not usually be expressed in a daughter, but a dominant gene on the X from the father will be expressed in the daughter. For a female to inherit a trait associated with an X-chromosome recessive gene, there must be two copies, one from each parent. Aside: The issue of gender-connected inherited traits has much more complexity than this simple discussion can address. For example, not all of the so-called male characteristics are carried on the male (Y) chromosome. The expression of genes on other chromosomes, from both the mother and father, is influenced by genes on the Y chromosome or simply by the absence of two X chromosomes. The reader should investigate further. Caveat: This discussion applies to humans and other mammals with the XX/XY sex determination system. See related links. Fun Fact: A woman discovered that the Y chromosome was male. While studying worms, in 1905, Nettie Stevens at Bryn Mawr College identified the Y chromosome as the determining factor in gender.
One of the main reasons genes assort independent of one another is that?
Genes on different chromosomes assort independently of each other by dint of the fact that they are on different chromosomes. The closer a gene is to another on the same chromosome the more likely they are to remain together even with crossing over.
What is the difference between recessive disorders and dominant disorders?
A sex linked dominant trait could be on the X chromosome of either parent and the phenotype of any individual carrier would be that of the dominant trait. A father with the dominant characteristic on his single X chromosome would produce daughters that are 100% carriers and would not pass the characteristic on to his sons. A mother who is a dominant X linked carrier would pass the dominant characteristic on to half hersons and half her daughters all of which would show the trait phenotypically. A sex linked recessive father would produce 100% carrier daughters. His sons would not get the recessive allele from him. A sex linked recessive carrier (heterozygous) mother would pass the trait on to 50% of her children and 50% of her sons would show the recessive trait genetics.
