Evolutionary perspectives on clonal reproduction in vertebrate animals

Abstract

A synopsis is provided of different expressions of whole-animal vertebrate clonality (asexual organismal-level reproduction), both in the laboratory and in nature. For vertebrate taxa, such clonal phenomena include the following: human-mediated cloning via artificial nuclear transfer; intergenerational clonality in nature via parthenogenesis and gynogenesis; intergenerational hemiclonality via hybridogenesis and kleptogenesis; intragenerational clonality via polyembryony; and what in effect qualifies as clonal replication via self-fertilization and intense inbreeding by simultaneous hermaphrodites. Each of these clonal or quasi-clonal mechanisms is described, and its evolutionary genetic ramifications are addressed. By affording an atypical vantage on standard vertebrate reproduction, clonality offers fresh perspectives on the evolutionary and ecological significance of recombination-derived genetic variety.cloning | asexuality | unisexuality | parthenogenesis | polyembryony

Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses?

“…a Anderson et al (2000) b,c,e Badoc et al (2002) a,d Baker et al (2010) b Holmes (2009Holmes ( b , 2013 a,b Buscaglia et al (2015) a Avise (2015) c Andersson (2012) a,b…”

“…It includes, not only mitotic clonality but also all cases where recombination is rare or absent (Tibayrenc et al, 1990), such as several cases of parthenogenesis, gynogenesis and hybridogenesis (Avise, 2004(Avise, , 2008(Avise, , 2015, as well as self-fertilization in homozygous states, strong inbreeding and 'unisexuality' . As we have shown (Tibayrenc and Ayala, 2012, 2013, 2014a, this definition is widely used by researchers working on population genetics of all kinds of micropathogens (Table 2).…”

“…As we have shown (Tibayrenc and Ayala, 2012, 2013, 2014a, this definition is widely used by researchers working on population genetics of all kinds of micropathogens (Table 2). It is also accepted by scientists working on unisexual vertebrates (Avise, 2004(Avise, , 2008(Avise, , 2015. Nevertheless, this definition is sometimes misunderstood, or not accepted by some researchers, who recommend distinguishing selfing/inbreeding from 'strict' clonality (see 'A debate in the debate: unisex/selfing/inbreeding versus "strict" clonality').…”

“…Extrensic causes include dispersal (bottleneck/founder effects leading to a deficiency of mating types and adaptation to new hosts) and hybridization between very divergent parental genotypes, leading to the impossibility of meiosis, a mechanism invoked also by Avise (2015) to explain asexuality in clonal vertebrates. Intrinsic causes include mitotic clonality, selfing and intratetrad mating.…”

“…Occasional bouts of recombination make it possible to benefit from virtually all the advantages of regular recombination (Birky, 2010;. In the case of sexual parasitism in vertebrates (gynogenesis, hybridogenesis), although populations are mainly clonal (Avise, 2015), occasional introgression ('genetic leakage') occurs (Lehtonen et al, 2013).…”