Question

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mitochondrial dna can be taken from bone, hair, or teeth and used in dna typing. what are the benefits to using mitochondrial dna over nuclear dna? choose three correct answers. mtdna is present in all maternal relatives of the person being investigated. mtdna is useful if the nuclear dna is degraded. mtdna is inherited from the mother and father’s egg cells, unlike nuclear dna. mtdna requires a much smaller sample than nuclear dna.

Explanation:

1. mtDNA requires a much smaller sample than nuclear DNA: Mitochondria are present in many copies per cell, so less tissue/sample is needed to extract sufficient mtDNA for analysis compared to nuclear DNA which is in two copies per cell (in diploid cells).
2. mtDNA is useful if the nuclear DNA is degraded: Since mtDNA is more resistant to degradation (due to multiple copies and protective proteins in mitochondria) than nuclear DNA, it can be analyzed when nuclear DNA is too damaged to use.
3. mtDNA is present in all maternal relatives of the person being investigated: mtDNA is inherited maternally, so all individuals in the maternal lineage (mother, grandmother, siblings from mother, etc.) will have the same (or very similar, barring rare mutations) mtDNA, allowing tracing of maternal ancestry or identification through maternal relatives.

The option "mtDNA is inherited from the mother and father’s egg cells, unlike nuclear DNA" is incorrect because mtDNA is inherited only from the mother (via the egg cell; sperm contributes little to no mtDNA to the zygote), while nuclear DNA is inherited from both parents.

Answer:

• mtDNA requires a much smaller sample than nuclear DNA.
• mtDNA is present in all maternal relatives of the person being investigated.
• mtDNA is useful if the nuclear DNA is degraded.