In an animal, how is the DNA from this organelle inherited?
In animals, the DNA present in the mitochondria is inherited maternally. This means that the mitochondrial DNA (mtDNA) is passed down from the mother to her offspring. During fertilization, the sperm contributes only nuclear DNA to the resulting zygote, while the egg contributes both nuclear DNA and mitochondrial DNA. As a result, all the mitochondrial DNA in an individual is derived from their mother. This pattern of inheritance is referred to as maternal inheritance or matrilineal inheritance.
In animals, DNA from organelles such as mitochondria is inherited in a process called maternal inheritance. Here is a step-by-step explanation:
1. Mitochondria are small, membrane-bound organelles found in the cytoplasm of cells. They have their own set of DNA, called mtDNA, which is separate from the nuclear DNA found in the cell's nucleus.
2. During sexual reproduction in animals, two gametes (egg and sperm) combine to form a zygote. The sperm contributes nuclear DNA, while the egg contributes both nuclear DNA and mitochondrial DNA.
3. The mitochondria in the sperm do not usually enter the egg during fertilization. Only the mitochondria in the egg are passed on to the next generation.
4. Therefore, the inheritance of mitochondrial DNA is solely through the mother. The mitochondrial DNA from the mother's egg is passed down to her offspring, while the father's mitochondrial DNA does not contribute to their offspring's mitochondrial genome.
5. This pattern of inheritance creates what is known as the maternal lineage. It means that all mitochondria in an individual's body come from their mother and can be traced back to their maternal ancestors.
6. Mutations in mitochondrial DNA can occur, leading to genetic variations that can be passed down through generations along the maternal line.
In summary, in animals, the DNA from mitochondria is inherited exclusively from the mother, following a pattern called maternal inheritance.