Question

What are the 3 patterns of inheritance?

Answer 1

Inheritance:

1. Inheritance is the natural process by which genetic traits are passed from parent to their offspring.
2. There are three types of inheritance.

Autosomal (Dominant and Recessive):

1. Autosomal dominance means that the trait requires only one allele from one parent to be expressed in the offspring.
2. The dominant allele masks the effects of the recessive alleles.
3. Autosomal recessive inheritance means that two recessive alleles are present in the offspring.
4. The trait is not invisible in parents due to recession but is visible in offspring due to combination.
5. Autosomal dominant: Huntington's disease.
6. Autosomal recessive: cystic fibrosis, sickle cell disease.

X-linked (Dominant and Recessive):

1. X-linked dominant inheritance means that a gene is involved in a particular trait on the X chromosome, and only one copy of the allele is sufficient to pass on that trait to the offspring.
2. It means that X-linked recessive inheritance means that the phenotype is always expressed in homozygous males and females by genes involved in the traits of the X chromosome.
3. Carriers are women who have only one copy of the hereditary gene.
4. X-linked dominant: fragile X syndrome
5. X-linked recessive: hemophilia, Fabry disease.

Mitochondrial:

1. Mitochondria contain unique DNA that is passed down from parent to offspring.
2. Mitochondrial DNA is inherited only from mothers.
3. Fathers do not contribute to mitochondrial inheritance.
4. Examples: Diabetes mellitus and deafness (DAD).