Simona Sanvito^1,2, Anna Fabiani^1,3, Filippo Galimberti¹

Show more
¹ Elephant Seal Research Group, Sea Lion Island, Falkland Islands.
² Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, México.
³ Dipartimento di Biologia, Università Degli Studi di Roma Tor Vergata, Roma, Italia.
Show less

Abstract: The determination of sex by simple observation is often difficult in marine mammals, even in sexually dimorphic species. Moreover, there is often the practical necessity to determine sex in samples that have been collected without handling or observing the subjects. In these cases, a molecular assay for sex determination is required. We adapted an assay that targets the zinc-finger region and is based on a single primer pair, to the Guadalupe fur seal, a near threatened species that has a very limited breeding range. First, we validated the assay with a sample of pups in which we determined the sex by direct observation during handling; second, we compared it to a more recent assay, based on two different primer pairs and, finally, we evaluated the effect of DNA quantity on its reliability. The assay that we tested produced excellent results and was more reliable than the other one based on two primers. Reliable results were also obtained when only remarkably small quantities of DNA were amplified. These results show the potential use of this molecular assay in case of non-invasive sampling, an overly common situation when dealing with species of problematic conservation status.

Keywords: Sex Determination, Sex-Linked Genetic Markers, Low-Invasive Sampling, Non-Invasive Sampling, Pinnipeds, Arctocephalus townsendi

Cite this paper: Sanvito, S. , Fabiani, A. and Galimberti, F. (2014) Sex Determination in the Near Threatened Guadalupe Fur Seal: Molecular Markers and Their Potential Applications. Open Journal of Animal Sciences, 4, 270-277. doi: 10.4236/ojas.2014.45034.

References

[1]   Wickens, P.A. and York, A.E. (1997) Comparative Population Dynamics of Fur Seals. Marine Mammal Science, 13, 241-292. http://dx.doi.org/10.1111/j.1748-7692.1997.tb00631.x

[2]   Aurioles-Gamboa, D., Elorriaga-Verplancken, F. and Hernández-Camacho, C.J. (2010) The Current Population Status of Guadalupe Fur Seal (Arctocephalus townsendi) on the San Benito Islands, Mexico. Marine Mammal Science, 26, 402-408. http://dx.doi.org/10.1111/j.1748-7692.2009.00350.x

[3]   Townsend, C.H. (1931) The Fur Seal of the California Islands with New Descriptive and Historical Matter. Zoologica, 9, 42-457.

[4]   Hubbs, C. (1956) Back from Oblivion. Guadalupe Fur Seal: Still a Living Species. Pacific Discovery, 9, 14-51.

[5]   Belcher, R.L. and Lee, T.E. (2002) Arctocephalus townsendi. Mammalian Species, 700, 1-5. http://dx.doi.org/10.1644/1545-1410(2002)700<0001:AT>2.0.CO;2

[6]   Gallo-Reynoso, J.P. (1994) Factors Affecting the Population Status of Guadalupe Fur Seal, Arctocephalus townsendi (Merriam, 1897), at Isla De Guadalupe, Baja California, Mexico. Ph.D. Thesis, University of California, Oakland.

[7]   Shaw, C.N., Wilson, P.J. and White, B.N. (2003) A Reliable Molecular Method of Gender Determination for Mammals. Journal of Mammalogy, 84, 123-128. http://dx.doi.org/10.1644/1545-1542(2003)084<0123:ARMMOG>2.0.CO;2

[8]   Beja-Pereira, A., Oliveira Paulo, R., Alves, C.D., Schwartz, M.K. and Luikart, G. (2009) Advancing Ecological Understandings through Technological Transformations in Noninvasive Genetics. Molecular Ecology Resources, 9, 1279-1301. http://dx.doi.org/10.1111/j.1755-0998.2009.02699.x

[9]   Piggott, M.P. and Taylor, A.C. (2003) Remote Collection of Animal DNA and Its Applications in Conservation Management and Understanding the Population Biology of Rare and Cryptic Species. Wildlife Research, 30, 1-13. http://dx.doi.org/10.1071/WR02077

[10]   Lachish, S., Passmore, A. and Jones, M. (2011) A New PCR Assay for Reliable Molecular Sexing of Endangered Tasmanian Devils (Sarcophilus harrisii) from Non-Invasive Genetic Samples. Conservation Genetics Resources, 3, 279-281. http://dx.doi.org/10.1007/s12686-010-9341-z

[11]   Alacs, E., Georges, A., FitzSimmons, N. and Robertson, J. (2010) DNA Detective: A Review of Molecular Approaches to Wildlife Forensics. Forensic Science, Medicine, and Pathology, 6, 180-194.
http://dx.doi.org/10.1007/s12024-009-9131-7

[12]   Robertson, B.C. and Gemmell, N.J. (2006) PCR-Based Sexing in Conservation Biology: Wrong Answers from an Accurate Methodology? Conservation Genetics, 7, 267-271. http://dx.doi.org/10.1007/s10592-005-9105-6

[13]   Brinkman, T. and Hundertmark, K. (2009) Sex Identification of Northern Ungulates Using Low Quality and Quantity DNA. Conservation Genetics, 10,1189-1193.http://dx.doi.org/10.1007/s10592-008-9747-2

[14]   Curtis, C., Stewart, B.S. and Karl, S.A. (2007) Sexing Pinnipeds with ZFX and ZFY Loci. Journal of Heredity, 98, 280-285. http://dx.doi.org/10.1093/jhered/esm023

[15]   Fabiani, A., Galimberti, F., Sanvito, S. and Hoelzel, A.R. (2004) Extreme Polygyny among Southern Elephant Seals on Sea Lion Island, Falkland Islands. Behavioral Ecology, 15, 961-969.
http://dx.doi.org/10.1093/beheco/arh112

[16]   Roberts, C. (2008) Modelling Patterns of Agreement for Nominal Scales. Statistics in Medicine, 27, 810-830. http://dx.doi.org/10.1002/sim.2945

[17]   Gales, N.J., Bowen, W.D., Johnston, D.W., Kovacs, K.M., Littnan, C.L., Perrin, W.F., Reynolds, J.E. and Thompson, P.M. (2009) Guidelines for the Treatment of Marine Mammals in Field Research. Marine Mammal Science, 25, 725- 736. http://dx.doi.org/10.1111/j.1748-7692.2008.00279.x

[18]   Sikes, R.S. and Gannon, W.L. (2011) Guidelines of the American Society of Mammalogists for the Use of Wild Mammals in Research. Journal of Mammalogy, 92, 235-253.
http://dx.doi.org/10.1644/10-MAMM-F-355.1

[19]   Lindenfors, P., Tulleberg, B.S. and Biuw, M. (2002) Phylogenetic Analyses of Sexual Selection and Sexual Size Dimorphism in Pinnipeds. Behavioral Ecology and Sociobiology, 52, 188-193.
http://dx.doi.org/10.1007/s00265-002-0507-x

[20]   McLaren, I.A. (1993) Growth in Pinnipeds. Biological Reviews, 68, 1-79.
http://dx.doi.org/10.1111/j.1469-185X.1993.tb00731.x

[21]   Sanvito, S., Galimberti, F. and Miller, E.H. (2007) Having a Big Nose: Structure, Ontogeny and Function of the Elephant Seal Proboscis. Canadian Journal of Zoology, 85, 207-220.
http://dx.doi.org/10.1139/z06-193

[22]   Broquet, T., Ménard, N. and Petit, E. (2007) Noninvasive Population Genetics: A Review of Sample Source, Diet, Fragment Length and Microsatellite Motif Effects on Amplification Success and Genotyping Error Rates. Conservation Genetics, 8, 249-260. http://dx.doi.org/10.1007/s10592-006-9146-5

[23]   Clutton-Brock, J. (2003) Risk Assessment for Animals: Should the Routine Assessment of Negative Effects of Intervention in Wild Animals Be Built into Research Projects? Journal of Zoology, 260, 117-118. http://dx.doi.org/10.1017/S095283690321356X

[24]   Russow, L.M. and Theran, P. (2003) Ethical Issues Concerning Animal Research Outside the Laboratory. ILAR Journal, 44, 187-190. http://dx.doi.org/10.1093/ilar.44.3.187

[25]   Sanvito, S., Galimberti, F., Sanvito, R. and Braschi, C. (2005) The “Seal Prick”: A Low Invasive Method for Blood Sampling in Male Elephant Seals. Marine Mammal Science, 21, 574-581.
http://dx.doi.org/10.1111/j.1748-7692.2005.tb01251.x

[26]   Green, D.S., Young, J.K., Henrandez-Camacho, C.J. and Gerber, L.R. (2010) Developing a Non-Invasive Indicator of Pinniped Health: Neonate Behavior and Growth in California Sea Lions (Zalophus Californianus). Ciencias Marinas, 36, 311-321. http://dx.doi.org/10.7773/cm.v36i3.1662

[27]   Swanson, B.J., Kelly, B.P., Maddox, C.K. and Moran, J.R. (2006) Shed Skin as a Source of DNA for Genotyping Seals. Molecular Ecology Notes, 6, 1006-1009.
http://dx.doi.org/10.1111/j.1471-8286.2006.01473.x

[28]   Peterson, R.S., Hubbs, C., Gentry, R.L. and DeLong, R.L. (1968) The Guadalupe Fur Seal: Habitat, Behavior, Population Size and Field Identification. Journal of Mammalogy, 49, 665-673.
http://dx.doi.org/10.2307/1378727

[29]   Fischbach, A.S., Jay, C.V., Jackson, J.V., Andersen, L.W., Sage, G.K. and Talbot, S.L. (2008) Molecular Method for Determining Sex of Walruses. Journal of Wildlife Management, 72, 1808-1812.
http://dx.doi.org/10.2193/2007-413

[30]   Sanvito, S., Schramm, Y. and Galimberti, F. (2012) Pvc74 Is Sex Linked in Elephant Seals (Genus Mirounga). Marine Mammal Science, 28, E191-E196.
http://dx.doi.org/10.1111/j.1748-7692.2011.00494.x