To Be, on Not to Be, Monoclonal

What is meant by the term ‘cloning’.
We can distinguish three different meanings:

1) cloning per se, or the copy of individuals that are identical with an original through asexual re-production. This is common in the plant kingdom (see video below) and in principle produces individual with the same genetic endowment, barring (epi)genetic mutations that can occur during the process. This parallels cellular mitosis but is achieved at the organismal level.

2) ‘cloning’ by Somatic Cell Nuclear Transfer (SNCT), produces a hybrid cell with the same nuclear DNA as the donor cell but without the same mitochondrial DNA which is endowed by the enucleated oocyte (see video below). Once it has developed in a surrogate mother, this 2 mothers/1 father clone is like a later-born identical twin of the clonee.

3) ‘cloning’ by embryo splitting (see video below), producing genetically-identical monozygotic (MZ) twins, but each resulting from the recombination of the genetic endowment of male and female gametes. This is relatively common in the human species with approximately 1 in 300 live births resulting in MZ twins. On average a pair of ‘human clones’ is born every 50 seconds. Another mammal, the nine-banded armadillo produces MZ quadruplets every time it breeds.

With these definitions in place, can we examine the morality of human cloning?

For the time being, scenario 1 needs not be debated here because this literal form of cloning does not refer (yet) to human cloning. This cloning refers to a common practice in horticulture, whereby a parent plant is propagated by cuttings or through a natural process known as somatic embryogenesis. Cloning in plants is made possible thanks to their ability to produce embryos without generating gametes or the need for sexual reproduction. This can also be achieved by planarians (see video below). When a adult flatworm is cut into multiple smaller pieces, each one can regrow (as clones) through a process referred to as regeneration. This property is not shared with humans.

Scenari 2 and 3 on the contrary, are important for the inference of an individual’s identity, its uniqueness, its idiosyncrasy. As such, it is pertinent to moral analysis. When ‘cloning’ by SCNT we produce a ‘clone’ whose identity could be inferred a priori. It is ‘vertical' cloning for the genotypical (and sometimes phenotypical) identity of the clonee is previously known.

In ‘cloning’ by embryo splitting we have two individuals whose genetic identity cannot be inferred ‘vertically’ based on information available a priori. This ‘horizontal’ form of cloning precludes intentional copying of the clonee and is preceded by sexual reproduction. Ab initio development of a hitherto unknown zygote is ensured by the successful conjugation of the maternal and paternal genomes which warrants the birth of two original copies: monozygotic twins.

Let us now consider the argument that opposes cloning. Based on the right to an un-manipulated genetic blueprint (i.e., non-reprogrammed), as a sine qua non condition for one's autonomy and sacred individuality, we begin to understand that the moral controversy can only operate for ‘clones’ obtained by SCNT (see video below) since nobody would reasonably think of morally condemning the existence of monozygotic twins.

To be continued ...

I want to touch on the subject of stem-cell derived Human Blastoids next. Once refined and equivalent to gamete-derived blastocysts, their legal and ethical standings will warrant thorough analysis.

November 5th, 2020

BrUno

To Be, or not to Be, Monoclonal