In heredity, is hemophilia recessive or dominant?
We usually don’t speak of Hemophilia as being recessive or dominant, since it’s an X-linked condition. But that makes it recessive. Sometimes it’s called “X-linked recessive.”If a person has one affected X-chromosome only (like an affected male), they will have the disease. If someone has one affected X-chromosome and one normal X-chromosome (like a carrier woman) they won’t have the disease. So one normal X dominates the one diseased X, so to speak. Normal is dominant here and Hemophilia is recessive.Make sense?
Hemophilia is caused by a recessive allele on the X chromosome.What is the father's genotype and phenotype?
The male's Genotype is either X with a superscript capital letter and Y, which means the male DOESN'T have hemophilia, or, the male could have an X with a superscript lower case letter and Y, which means he's a hemophiliac male. Phenotype: If the X has a superscript capital letter, then the phenotype is: a normal male (the capital letter signifies that the X is dominant) If the X has a superscript lowercase letter, then the phenotype is: a hemophiliac male (the lowercase letter signifies that the X is recessive). *Note: The Y- chromosome is too short to cover up any X chromosome. So, if the X has a recessive allele (which means the lowercase letter), then the male is going to have hemophilia. I hope this makes sense! :)
Hemophilia is a sex-linked trait caused by a recessive allele. (“N” normal “n” recessive) A woman who is a car?
Hemophilia is a sex-linked trait caused by a recessive allele. (“N” normal “n” recessive) A woman who is a carrier for hemophilia marries a normal man. a.Create a punnett square b. What are the phenotypic ratios of the possible gametes? so i dont know how to do this at all. please help! especially about how to determine what percent of the males and females would be either carriers, unaffected or have the disease. thanks so much!
Human Genetics: Hemophilia is due to a recessive sex-linked gene?
a. The man has hemophilia, which means that he has one hemophilia positive X chromosome (Xh) and one Y chromosome (Y), which doesn't have a gene for clotting. Half of the time he will pass on the Xh chromosome, and half of the time he will pass on the Y chromosome. Because the woman's father had hemophilia and she is normal, she must be heterozygous for the hemophilia gene, because her father was incapable of giving her a normal clotting gene, as he had none himself, and if she was homozygous for the defective clotting gene she would have hemophilia. So her genotype is Xh X, and half of the time she will pass on a hemophilia positive X, and the other half of the time she will pass on an X with a normal clotting gene. Their children's genotypes will be: 1/2 Xh * 1/2 Xh = 1/4 Xh Xh 1/2 Xh * 1/2 X = 1/4 Xh X 1/2 Y * 1/2 Xh = 1/4 Xh Y 1/2 Y * 1/2 X = 1/4 X Y This means that their children's phenotypes will be 1/4 girls with hemophilia 1/4 girls with normal clotting 1/4 boys with hemophilia 1/4 boys with normal clotting b. I will denote aniridia with an A and the recessive gene with an a. In a similar fashion, the migraine gene will be M and the recessive non-migrane gene will be m. The man must have on A gene if he has aniridia, but his mother must have had all a genes, so his genotype must be Aa. Since migranes aren't mentioned, we can presume that his genotype with respect to migraines must be mm. This means that he will pass on Am 1/2 of the time and am 1/2 of the time. The woman must be Mm if she suffers from migraines but her father did not, and with respect to aniridia she must be aa. This means that 1/2 of the time she will pass on aM, and half of the time she will pass on am. The genotypes of their children will be: 1/2 Am * 1/2 aM = 1/4 AaMm 1/2 Am * 1/2 am = 1/4 Aamm 1/2 am * 1/2 aM = 1/4 aaMm 1/2 am * 1/2 am = 1/4 aamm Their children's phenotypes will be: 1/4 suffer from migraines and aniridia (ouch!) 1/4 suffer from aniridia but not migraines 1/4 suffer from migranes but not aniridia 1/4 suffer from neither I hope this helps! FYI, this is basis genetic stuff. You should see what I'm doing it my college genetics class.
Hemophilia in humans is X-linked. Hemophilia (h) is caused by a recessive gene. Normal blood clotting time..?
Let's do a Punnet Square to visualize this. What we have is a heterozygous mother (meaning she has both H and h), XH Xh, and a normal male, XH Y. The Y chromosome does not carry a gene for this trait. That gives us: ---------XH---------- Xh XH---- XHXH----- XHXh Y------- XHY-------- XhY (Sorry about the dashes, but without them, it moves them out of place :/ ) Therefore, we see that we have only one child with Hemophilia, and that child is male. The other male has the normal gene (H), one of the females has both (H), and the other female is heterozygous. Remember, however, that the dominant gene (H), overrides the recessive gene. The chances of having a child with abnormal clotting rates (a child with hemophilia), would be 25% I hope you see how I did this so you can do it on your own-- good luck!
What are the types of dominant and recessive alleles in heredity?
Since human cells carry two copies of each chromosome? they have two versions of each gene?. These different versions of a gene are called alleles?.Alleles can be either dominant? or recessive?.Dominant alleles show their effect even if the individual only has one copy of the allele (also known as being heterozygous?). For example, the allele for brown eyes is dominant, therefore you only need one copy of the 'brown eye' allele to have brown eyes (although, with two copies you will still have brown eyes).If both alleles are dominant, it is called codominance?. The resulting characteristic is due to both alleles being expressed equally. An example of this is the blood group AB which is the result of codominance of the A and B dominant alleles.Recessive alleles only show their effect if the individual has two copies of the allele (also known as being homozygous?). For example, the allele for blue eyes is recessive, therefore to have blue eyes you need to have two copies of the 'blue eye' allele.Some genes are found on the sex chromosome?, X.These genes are inherited with the X chromosome (from the mother if it is a boy or from either mother or father if it is a girl).Females have two X chromosomes (XX), while males have one X chromosome and one Y chromosome (XY).This means females have two alleles for X-linked genes while males only have one.Some genetic diseases, are caused by sex linked genes, for example haemophilia?.The allele for haemophilia is recessive so two copies are needed for a female to have the diseaseHowever, because males only have one X chromosome, they only need one copy of the haemophilia allele to have the disease.This means haemophilia is much more common in males than in females.For example:Functioning allele = HHemophilia allele = hXHXH= healthy femaleXHXh= carrier?femaleXhXh= hemophilia femaleXHY = healthy maleXhY = hemophilia male
If hemophilia is recessive and sits on the x-chromosome, why can women only be a carrier of the disease?
The idea that women cannot have hemophilia is a misconception. Women “carriers” of a gene for hemophilia can, and frequently do, have mild hemophilia and much less commonly, moderate or severe hemophilia. As you know, women have two X chromosomes, only one of which can be active in a cell. In the past, it was assumed that the inactivation of one of the X chromosomes was a more or less random process (called Lyonization), however we have found this is not always the case: sometimes more, or all, the X chromosomes from one parent are inactivated. In addition to both parents carrying the gene for hemophilia mentioned in other posts, a woman may have hemophilia as a result of inactivating most or all of the X chromosomes from one parent (non-random X chromosome inactivation)—if she inactivates all of “good” X chromosomes, she will have severe hemophilia. If she inactivates more than half of the “good” X chromosomes, she will mild or moderate hemophilia. Also, for unknown reasons, women tend to experience more bleeding problems than men with the same factor level. Women with less than 60% factor level (low normal) have an increased risk of bleeding problems, and the lower the factor level the higher the risk.
Why is hemophilia considered autosomal?
Haemophilia is not an autosomal disease,it is an X-linked recessive traitAn X linked disease is one in which a mutation of a gene on the X chromosome causes the phenotype to be expressed only in males (who are hemizygous as they have X and Y chromosomes) and rarely females (who are necessarily homozygous i.e. both the X chromosomes affected)Females with one X chromosome affected are only carriers as it is a recessive disease but they can transfer the disease to 50% of their male progenyOne famous example is the British Royal family ,queen Victoria was suspected to be a carrier of haemophilia thus giving rise to the phrase ‘of blue blood’