Multiple paternity in Chinese alligator (Alligator sinensis) clutches during a reproductive season at Xuanzhou Nature Reserve

Abstract

Paternity testing was determined in Chinese alligator (Alligator sinensis) clutches during a reproductive season at Xuanzhou Nature Reserve, using five microsatellite loci. DNA from ten mother and offspring clutches was analysed to identify paternal alleles. Three or four paternal alleles were observed among three of ten clutches. These clutches were sired by at least two different males. This present study confirmed the effectiveness of microsatellite DNA markers in detecting multiple paternity within natural populations of Chinese alligator. However, to reduce the confounding effects of mutations and null alleles on allele assignment and to increase power to monitor individual's genetic contribution, we need additional variable genetic markers.

Mating dynamics and multiple paternity in a long‐lived vertebrate

“…Crocodilians, which have widely varying population densities and degrees of male territoriality, provide an excellent system to explore the evolutionary and ecological drivers that underlie the observed variation in the frequency of multiple paternity (Amavet, Rosso, Markariani, & Piña, 2008;Budd, Spotila, & Mauger, 2015;Davis, Glenn, Elsey, Dessauer, & Sawyer, 2001;Lance et al, 2009;Lewis, FitzSimmons, Jamerlan, Buchan, & Grigg, 2013;Mcvay et al, 2008;Muniz et al, 2011;Ojeda, Amavet, Rueda, Siroski, & Larriera, 2017;Oliveira, Marioni, Farias, & Hrbek, 2014;Lafferriere et al, 2016;Wu & Hu, 2010). The frequency of multiple paternity observed across crocodilian taxa ranges from 32% in the Chinese alligator (Alligator sinensis) to 100% in black caiman (Melanosuchus niger) (Muniz et al, 2011;Wu & Hu, 2010). Among crocodilians, it is not clear if the frequency of multiple paternity is driven by population density and/or mate encounter rate (Amavet et al, 2008;Budd et al, 2015;Davis et al, 2001;Lance et al, 2009;Lewis et al, 2013;McVay et al, 2008;Muniz et al, 2011;Oliveira et al, 2014;Lafferriere et al, 2016;Wu & Hu, 2010) though both have been suggested (Budd et al, 2015;Lafferriere et al, 2016).…”

“…The frequency of multiple paternity observed across crocodilian taxa ranges from 32% in the Chinese alligator (Alligator sinensis) to 100% in black caiman (Melanosuchus niger) (Muniz et al, 2011;Wu & Hu, 2010). Among crocodilians, it is not clear if the frequency of multiple paternity is driven by population density and/or mate encounter rate (Amavet et al, 2008;Budd et al, 2015;Davis et al, 2001;Lance et al, 2009;Lewis et al, 2013;McVay et al, 2008;Muniz et al, 2011;Oliveira et al, 2014;Lafferriere et al, 2016;Wu & Hu, 2010) though both have been suggested (Budd et al, 2015;Lafferriere et al, 2016).…”

How many fathers? Study design implications when inferring multiple paternity in crocodilians

“…From Table 1, when the total number of alleles for each crocodilian parentage analysis study are tallied, the number of alleles varies from 24 (Amavet et al, 2012; Hu & Wu, 2010) to 91 alleles (Oliveira et al, 2014) with an average of 42 total alleles equivalent to the 5H panel used herein. Following from the findings in this study and given that nest assignment is possible in crocodilians if offspring are being sampled from eggs/embryos, when fewer alleles are available, using GERUD 2.0 or the SLMM is sufficient to accurately infer sire number.…”

“…Understandably, it is not always possible or safe to take a tissue or blood sample from any adult crocodilian. However, at the very least, maternal DNA was successfully extracted from the membrane of unfertilized eggs in the Chinese alligator ( Alligator sinensis ; Hu & Wu, 2010), fetal membranes of the Nile crocodile ( Crocodylus niloticus ; Nöthling et al, 2020), and from the eggshell matrix in birds (e.g., Egloff et al, 2009). Extraction of environmental DNA (eDNA) from soil samples in direct contact with the eggs when the nest is opened may also be a useful source of maternal DNA (Adams et al, 2019) from mucous residue which is present on eggs at the time of oviposition.…”