0
Sex-linked diseases are inherited through one of the "sex chromosomes" -- the X or Y chromosomes. Autosomally inherited diseases are inherited through the non-sex chromosomes (autosomes), pairs 1 through 22.
Dominant inheritance occurs when an abnormal gene from one parent is able to cause disease even though the matching gene from the other parent is normal. The abnormal gene dominates.
Recessive inheritance occurs when both matching genes must be abnormal to produce disease. If only one gene in the pair is abnormal, the disease does not show up or is mild. Someone who has one abnormal gene (but no symptoms) is called a carrier. A carrier can pass this abnormal gene to his or her children.
The term "sex-linked recessive" usually refers to X-linked recessive.
See also:
- Autosomal dominant
- Autosomal recessive
- Chromosome
- Gene
- Genetic counseling and prenatal diagnosis
- Heredity and disease
- Inheritance
- Sex-linked dominant
Inheritance - sex-linked recessive; Genetics - sex-linked recessive; X-linked recessive
InformationX-linked diseases usually occur in males. Males have only one X chromosome. A single recessive gene on that X chromosome will cause the disease.
The Y chromosome is the other half of the XY gene pair in the male. However, the Y chromosome doesn't contain most of the genes of the X chromosome. It therefore doesn't protect the male. This is seen in diseases such as hemophilia and Duchenne muscular dystrophy.
TYPICAL SCENARIOS
For a given birth, if the mother is a carrier (only one abnormal X chromosome) and the father is normal:
- 25% chance of a normal boy
- 25% chance of a boy with disease
- 25% chance of a normal girl
- 25% chance of a carrier girl without disease
If the father has the disease and the mother is normal:
- 100% chance of a normal boy
- 100% chance of a carrier girl without disease
X-LINKED RECESSIVE DISORDERS IN FEMALES
Females can get an X-linked recessive disorder, but this is very rare. An abnormal gene on the X chromosome from each parent would be required, since a female has two X chromosomes. This could occur in the two scenarios below.
For a given birth, if the mother is a carrier and the father has the disease:
- 25% chance of a healthy boy
- 25% chance of a boy with the disease
- 25% chance of a carrier girl
- 25% chance of a girl with the disease
If the mother has the disease and the father has the disease:
- 100% chance of the child having the disease, whether boy or girl.
The odds of either of these two scenarios are so low that X-linked recessive diseases are sometimes referred to as "male only" diseases. However, this is not technically correct.
Female carriers can have a normal X chromosome that is abnormally inactivated. This is called "skewed X-inactivation." These females may have symptoms similar to those of males.
What else can I help you with?
Is hemophilia a dominantrecessiv or a sex linked trait?
Sexlinked and recessive.
Is it true that sexlinked recessive disorders are most often passed from mothers to sons?
true
How long do chocolate Bastin Homing pigeons live?
Chocolate is a regional name used by racing pigeon breeders for a recessive opal pigeon. All racing pigeons can live up to about 12-15 years with a rare number of them living to about 20. And even though you didn't specifically ask this, recessive opal is a non-sexlinked (autosomal) recessive.
Is color blindness a dominant or a recessive trait?
Color blindness is a recessive trait, meaning that an individual needs to inherit two copies of the gene for color blindness (one from each parent) in order to be color blind. If an individual inherits only one copy of the gene, they are considered a carrier and will not exhibit color blindness.
Can a person be a carrier for a dominant genetic disorder?
Anyone can be a carrier of a recessive genetic disorder (as long as it is not associated with the sex chromosomes) no matter what their gender since "carrier" refers to an individual that is heterozygous for the recessive allele and therefore phenotypically normal. Specifically, sexlinked genetic disorders can be "carried" by a heterozygous female but males (having only one X chromosome) cannot. Males will either be free of the defective gene or be affected.
Can males be carriers of sexlinked traits?
No. Carriers are people that carry the gene for something but exhibit no phenotype for it. Since males have no extra copy to hide a recessive trait, they cannot be carriers for sex linked traits.Answ2. Followers of this question should consult say haemophilia in wikipedia.com.
A trait that is hidden?
The trait that is hidden is recessive trait.
How do you xxplain dominant and recessive?
Recessive
Is leukemia a recessive gene?
recessive.
Is AAA recessive or dominant?
recessive
When is a recessive allel expressed in offspring?
A recessive phenotype is expressed in an offspring that has a homozygous recessive genotype for that trait.
Which alleles is the recessive alleles?
Recessive alleles are alleles that are masked or overshadowed by dominant alleles. In a heterozygous genotype, the recessive allele does not show its effects. Only in a homozygous recessive genotype does the recessive allele manifest its trait.
