Q23 - Nuclear and Mitochondrial DNA Origin After Nuclear Transfer

Theoretical B Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Recombinant DNA & Biotechnology Techniques

Researchers succeeded in reprogramming human somatic cells into embryonic stem cells (ESC) by a somatic cell nucleus transfer (SCNT) into oocytes from which the nucleus had been removed. After the transfer, the origin of the nuclear and mitochondrial (mt) DNA were analysed (Fig.).

Nuclear DNA genotyping from three nucleus transfer (NT)-ESC lines (NT1-3) determined by microsatellite analysis; D2S1333 and D4S413 are locus names and numbers in columns are sequence length of specific alleles.

mtDNA sequences of the NT-ESC lines (HF = human foetus); 16187 and 16193 are two nucleotide positions used as markers after SCNT (from Tachibana et al. 2013).

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. The nuclear DNA composition of the ESCs is a combination of nuclear DNA from the somatic donor cell and nuclear DNA from the oocyte donor

B. The mtDNA of the ESC lines originates from the oocyte

C. After nuclear transfer the oocyte becomes a haploid

D. It is most likely, that different oocyte donors were used

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Question reproduced from IBO 2015, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)