A veterinary research team uses Somatic Cell Nuclear Transfer (SCNT) to clone a high-yielding dairy cow, Cow X (a Holstein-Friesian breed). A somatic mammary cell is harvested from Cow X, and its nucleus is transferred into an enucleated oocyte obtained from Cow Y (a Jersey breed). After activation, the reconstructed embryo is implanted into the uterus of a surrogate, Cow Z (a Guernsey breed), which carries the pregnancy to term and delivers a healthy calf.
Which of the following statements regarding the genetic composition and biological characteristics of the cloned calf is correct?
The cloned calf's nuclear genome is identical to Cow X, but its mitochondrial DNA (mtDNA) is inherited from Cow Y, meaning its cellular respiration and metabolic efficiency may differ from Cow X.
Since the oocyte was fully enucleated, Cow Y contributes no genetic material to the cloned calf, making the clone genetically identical to Cow X in both its nuclear and cytoplasmic genomes.
Epigenetic reprogramming during SCNT completely resets the DNA methylation and histone modification patterns of the donor nucleus to match those of a natural zygote, preventing any developmental abnormalities.
The surrogate mother (Cow Z) contributes to the calf's nuclear genotype during gestation via the horizontal transfer of chromosomal DNA across the placental barrier.
