[Progress on abnormal development of cloned pigs generated by somatic cell transfer nuclear]

Area of Science:

• Animal Science
• Reproductive Biology
• Biotechnology

Background:

• Somatic cell nuclear transfer (SCNT) enables cloning pigs for various applications, including breeding and genetic modification.
• Despite its potential, pig cloning efficiency is severely limited by developmental defects and high mortality rates.
• Epigenetic reprogramming errors in the donor nucleus are primary contributors to these cloning failures.

Purpose of the Study:

• To review the abnormal phenotypes and underlying causes of developmental issues in cloned pigs.
• To summarize effective strategies for enhancing pig cloning efficiency.
• To provide insights for future research aimed at improving cloned pig development and survival.

Main Methods:

• Literature review of studies on pig cloning, epigenetic reprogramming, and developmental abnormalities.
• Analysis of reported phenotypes, including birth rate, birth weight, stillbirth, mortality, and malformations.
• Evaluation of methods proposed to improve epigenetic reprogramming and overall cloning success.

Main Results:

• Cloned pigs exhibit significant developmental defects, such as low birth rates, low birth weight, and high incidences of stillbirth, neonatal mortality, and congenital malformations.
• Errors in epigenetic reprogramming of donor cells are strongly implicated as the main cause of these defects.
• Current methods to correct epigenetic errors have not substantially improved birth and survival rates in cloned pigs.

Conclusions:

• Abnormal epigenetic reprogramming is a critical barrier to successful pig cloning.
• Further research is needed to develop more effective strategies to overcome these reprogramming errors.
• Improving epigenetic reprogramming is essential for enhancing the developmental and survival rates of cloned pigs and their embryos.