Explain any three mendelian disorder
Dear student.
Mendelian Genetic Disorders is of four types:
Autosomal dominant: Autosomal dominant disorders are those types of Mendelian disorders which are caused due to the inheritance of mutated dominant genes which carry the alleles for the disorder. Each affected individual usually has one affected parent. These types of disorder tend to occur in every generation of an affected family. Ex- Myotonic dystrophy
Autosomal recessive: Autosomal recessive disorders are those types of Mendelian disorders which are caused due to the inheritance of mutated recessive genes which carry the alleles (recessive) for the disorder. In case of autosomal recessive, unaffected parents can have affected offspring. Parents are carrier (heterozygous) of the disorder to produce affected offspring. Autosomal recessive disorders are typically not seen in every generation of an affected family. For example sickle cell anaemia.
Sex-linked dominant: Sex linked dominant trait means that gene for disorder is present on X chromosome and one copy of gene i.e heterozygous condition is sufficient to cause disease. For example, fragile X syndrome
Sex-linked recessive: Sex-linked recessive trait refers to the condition in which the gene controlling a specific trait is present in its recessive form on the X-chromosome. You might be knowing that humans have 23 pairs of chromosomes, out of which 22 are autosomes and the one pair is sex chromosomes. Males have 22+XY chromosomes while females have 22+XX chromosomes. If any trait is recessive, then two copies of the gene is required for its expression. One such example for X-linked recessive trait is the gene coding for the disease haemophilia. Haemophilia is a congenital disease (hereditary disease) that is caused by the deficiency of Factor VIII, an important clotting factor. The mutation in this gene leads to this deficiency. The gene for this factor is carried on the X-Chromosome. This gene appears in the normal (dominant) and the mutant (recessive form). Because females have two X chromosomes while males have only one X chromosome, for a female to get affected by haemophilia she has to have the mutant gene on both the X chromosomes while males may be affected if the carry it on the one X chromosome. Moreover, haemophilia in females is lethal condition and these females may not survive past their childhood.
Regards.
Mendelian Genetic Disorders is of four types:
Autosomal dominant: Autosomal dominant disorders are those types of Mendelian disorders which are caused due to the inheritance of mutated dominant genes which carry the alleles for the disorder. Each affected individual usually has one affected parent. These types of disorder tend to occur in every generation of an affected family. Ex- Myotonic dystrophy
Autosomal recessive: Autosomal recessive disorders are those types of Mendelian disorders which are caused due to the inheritance of mutated recessive genes which carry the alleles (recessive) for the disorder. In case of autosomal recessive, unaffected parents can have affected offspring. Parents are carrier (heterozygous) of the disorder to produce affected offspring. Autosomal recessive disorders are typically not seen in every generation of an affected family. For example sickle cell anaemia.
Sex-linked dominant: Sex linked dominant trait means that gene for disorder is present on X chromosome and one copy of gene i.e heterozygous condition is sufficient to cause disease. For example, fragile X syndrome
Sex-linked recessive: Sex-linked recessive trait refers to the condition in which the gene controlling a specific trait is present in its recessive form on the X-chromosome. You might be knowing that humans have 23 pairs of chromosomes, out of which 22 are autosomes and the one pair is sex chromosomes. Males have 22+XY chromosomes while females have 22+XX chromosomes. If any trait is recessive, then two copies of the gene is required for its expression. One such example for X-linked recessive trait is the gene coding for the disease haemophilia. Haemophilia is a congenital disease (hereditary disease) that is caused by the deficiency of Factor VIII, an important clotting factor. The mutation in this gene leads to this deficiency. The gene for this factor is carried on the X-Chromosome. This gene appears in the normal (dominant) and the mutant (recessive form). Because females have two X chromosomes while males have only one X chromosome, for a female to get affected by haemophilia she has to have the mutant gene on both the X chromosomes while males may be affected if the carry it on the one X chromosome. Moreover, haemophilia in females is lethal condition and these females may not survive past their childhood.
Regards.