Sex-linked inheritance and autosomal inheritance are two types of inheritance patterns. Sex-linked inheritance occurs via the genes located in the sex chromosomes. Whereas, autosomal inheritance occurs via the genes in autosomes. Both types of inheritance exist as two types: recessive and dominant. However, autosomal inheritance occurs in equal frequency in males and females while it affects males and females differently in sex-linked inheritance.
However, studying sex-linked inheritance is easy than studying autosomal inheritance. Thus, this summarizes the difference between sex-linked and autosomal. Samanthi Udayangani holds a B. Degree in Plant Science, M. Your email address will not be published. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.
What are the different ways a genetic condition can be inherited? From Genetics Home Reference. These conditions are usually inherited in one of several patterns, depending on the gene involved: Patterns of inheritance Inheritance pattern Description Examples Autosomal dominant One altered copy of the gene in each cell is sufficient for a person to be affected by an autosomal dominant disorder.
Huntington disease , Marfan syndrome Autosomal recessive In autosomal recessive inheritance , variants occur in both copies of the gene in each cell.
Y chromosome infertility , some cases of Swyer syndrome Codominant In codominant inheritance , two different versions alleles of a gene are expressed, and each version makes a slightly different protein. ABO blood group, alpha-1 antitrypsin deficiency Mitochondrial Mitochondrial inheritance , also known as maternal inheritance, applies to genes in mitochondrial DNA.
Leber hereditary optic neuropathy LHON Many health conditions are caused by the combined effects of multiple genes described as polygenic or by interactions between genes and the environment. Topics in the Inheriting Genetic Conditions chapter What does it mean if a disorder seems to run in my family?
Why is it important to know my family health history? If a genetic disorder runs in my family, what are the chances that my children will have the condition? What are reduced penetrance and variable expressivity? The only possible way to inherit this disease, then, would be through the inheritance of the father's Y-chromosome. Women have two X-chromosomes, one from each parent, and could not possibly pass down the disorder. Epigenetic inheritance could potentially explain a genetic disorder, but, if this were the case, it should not differentiate between males and females.
Abnormal testosterone levels may be a result of the disorder, but they do no explain how the disorder is inherited. Individuals with Klinefelter syndrome are phenotypically male, but experience reduced sperm production and breast development in adolescence.
What meiotic error gives rise to this condition? Aneuploidy is a chromosomal condition in which there are an abnormal number of chromosomes in the cells of the body. Aneuploidy typically refers to monosomy one chromosome copy or trisomy three chromosome copies , and arises due to nondisjunction during meiosis and gametogenesis. Nondisjuction causes one daughter cell to receive three or four chromatids, and the other to receive one or zero.
If this gamete is used to form a zygote, all cells in the resulting offspring will carry the abnormal chromosome number. Translocation occurs when chromosomal fragments join non-homologous chromosomes. Polyploidy is a condition in which a cell has more than two complete chromosomal sets; in this example, only one set of chromosomes carries three copies. Duplication is the presence of additional segments within a single chromosome.
Red-green colorblindness is an X-linked recessive disorder. Which of the following scenarios is not a possible method by which this disorder can be inherited? X-linked disorders are inherited when a parent passes on his or her X-chromosome. Since females have two X-chromosomes, they are less likely to exhibit symptoms of a recessive disorder than males, who have only one.
Females are capable of carrying a recessive X-linked trait without expressing it, while males are not. A male must inherit his Y-chromosome from the father and an X-chromosome from the mother, while a female must inherit X-chromosomes from both parents. If a genotypically healthy mother and a colorblind father have a son, then this child must inherit an X-chromosome from the mother and a Y-chromosome from the father.
The mother's chromosome are both genotypically normal, and do not possess the colorblind allele. This means that the son cannot possibly inherit a colorblind allele if the mother is genotypically normal. Colorblindness is a recessive X-linked disorder. A genotypically normal man and a colorblind woman have two sons and one daughter.
What is the probability that one son is colorblind and the other two children are phenotypically normal? The Punnett square below represents the couple's possible offspring, with the mother having genotype and the father having genotype. Since the disorder is X-linked, we know that any sons will necessarily inherit an affected allele from the mother. Any daughters will inherit an chromosome from each parent; by necessity, any daughters will be heterozygous carriers.
The question states that the couple had two sons and one daughter, and asks the probability that one son is colorblind, one son is normal, and one daughter is colorblind. In this pedigree, affected individuals have a disease causing the person to be born with feathers instead of hair, called Disease P. The first generation shows us a father with the disease and a mother without the disease. They produce three children, none of whom have the disease. Knowing that they do not have the disease allows us to eliminate dominant from consideration.
In order for the third generation to be affected, the mother from the second generation must be a carrier. In the third generation, we see that the carrier mother has a male child with the disease with a father who does not have the disease. The male child will inherit the Y chromosome from his father, but must receive an X chromosome from the mother. He inherits the disease on this X chromosome.
Were the disease autosomal recessive, the father of the third generation child would need to be affected in order for him to inherit the trait. The disease must be X-linked recessive. In flies, red eyes is a wildtype trait with the allele. Male-to-male transmission can also be observed in autosomal dominant inheritance since a single mutated allele is sufficient for the expression of the trait. Huntington disease, Marfan syndrome, and myotonic muscular dystrophy are examples of autosomal dominant inheritance.
The autosomal dominant inheritance is shown in figure 1. Figure 1: Autosomal Dominant Inheritance. Both copies of genes are mutated in autosomal recessive inheritance.
Each mutated gene can be inherited from a parent who serves as the carrier for the trait. Cystic fibrosis and sickle cell anemia are two examples of autosomal recessive inheritance. X-linked inheritance refers to a pattern of inheritance in which the transmission of traits depends on the genes in the sex chromosomes. The two types of X-linked inheritance are X-linked dominant inheritance and X-linked recessive inheritance.
Mutation in the genes of the X chromosome causes the X-linked recessive disorders. Females have two X chromosomes while males have X and Y chromosomes. In females, both X chromosomes should have the mutation in order to be affected by the disease. In males, the mutation should occur on their X chromosome. Since the possibility of the occurrence of two mutated alleles in females is less, most females are not affected by the disease.
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