​The mitochondrial replacement therapy can be done either before or after in vitro fertilization.
Two mitochondrial replacement techniques have been developed, maternal spindle transfer and pronuclear transfer.
In maternal spindle transfer, the chromosome spindle apparatus of the carrier mother is removed from her unfertilized oocyte and inserted into the donor mother’s unfertilized and enucleated oocyte that contains normal mtDNA.
In pronuclear transfer, both carrier mother’s and donor mother’s oocytes are first fertilized in vitro.
The carrier mother’s pronucleus is inserted into the donor mother’s enucleated oocyte containing normal mtDNA, and the embryo is implanted into the carrier mother by IVF.
The mitochondrial replacement approach is generic; instead of targeting a specific mutation, MRTs replace nearly all mitochondria and their resident mtDNA and so could be applied to any inherited
mtDNA disease. Hence, statement 1 is correct.
Mitochondria are the organelle that contains DNA in circular form, and in animals, it is the only organelle in addition to the nucleus which contains DNA and gene.
The sperm contains a very low number of mitochondria and mitochondrial genes. So, in the offspring, the mitochondrial genes are inherited from the mother.
Thus, a father with a mitochondrial gene defect cannot transmit the disease to his offspring. Hence, statement 2 is correct.