**Table 3.**

**127**

*Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats*

tissues such as the liver and kidneys. Another benefit of using blood tissue is that an organism immune response can be observed between the levels of essential (Zn, Cu and Se) and toxic (Hg, Pb and Cd) metals, which suggests that there is a detoxification process by the organism due to the formation of metallothioneins (MT), which

At present, it is unknown to what degree chemical pollutants are harmful sea turtle health, since the concentration of each metal vary between species and populations, due to the fact that several factors influence the pollutant load, such as habits, diet and the levels of pollutants found in its food, sex, age and physical condition, exposure time, as well as the local habitat characteristics and climatic conditions [40–44]. For this reason, the monitoring of heavy metals in sea turtles

Sea turtles are sentinel species due to their sensitivity to environmental pollutants which can be analysed in their tissues and reflect the bioaccumulation and behaviour of pollutants such as heavy metals in the environment in which they live. This allows for the identification of potential threats to the environment and

Regarding the Kemp's ridley turtle (*Lepidochelys kempii*), different authors point out that their population within the Gulf of Mexico is exposed to the heavy metal concentrations present in water and sediments, highlighting that the main sources of contamination in the area are due to large oil spills, such as IXTOC-I in 1979 and Deepwater Horizon in 2010, which increased the concentrations of Pb and other toxic elements, causing potential risks to biota. However, few studies [46] have been carried out on the levels of heavy metals in this sea turtle (**Table 3**), these studies observed that the concentrations of Pb increased with turtle size in a foraging area in Texas, USA, while in another foraging area in Louisiana, USA, Cu and Hg accumulated in higher concentration related to size. On the other hand, this relationship was not observed in the population of the southeast Atlantic. These regional differences were attributed to geographic differences, sources of contamination and levels of metals in the blue crab (*Callinectes sapidus*), the main component of the

These differences observed in Kemps ridley turtles and the interspecific variability of the pollutant load due to the factors described above, show the importance of periodically monitoring the levels of heavy metals in the Gulf of Mexico and in this sea turtle, which would expand knowledge about the levels of these pollutants in the Gulf of Mexico and the impact on the health of this species, contributing to better care and management in *L. kempii* sea turtle conservation programs.

The study and analysis of nucleic acids in sea turtles has different approaches which depend on what type of nucleic acid is used to understand what, how and when to conduct molecular analysis. The application of genetics to improve species conservation efforts is an area with great potential, and there is a growing interest

All organisms or protein entities (such as viruses that contain DNA or RNA inside them) have different nucleic acid sequences (DNA or RNA). Variations are due to factors, such as differences between two individuals, which can be caused due to the time and space where they live, their biology, reproductive success, demographics, places and time of migrations and even natural selection. All the genetic information of each species is stored in its DNA; therefore, if its genome is analysed, it is possible to obtain this information for almost any evolutionary process. In conservation, the acquisition of this knowledge is important for identifying

must be carried out for each species on a regional and population level.

*DOI: http://dx.doi.org/10.5772/intechopen.96655*

health [45].

Kemp's ridley's diet.

**4.4 Molecular studies**

in this research.

are proteins that function as a detoxifying agent.

*Heavy metal concentrations reported in different areas (mean ± standard deviation,* μ*g g−1 wet weight) in L. kempii blood [46–48].*

#### *Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats DOI: http://dx.doi.org/10.5772/intechopen.96655*

tissues such as the liver and kidneys. Another benefit of using blood tissue is that an organism immune response can be observed between the levels of essential (Zn, Cu and Se) and toxic (Hg, Pb and Cd) metals, which suggests that there is a detoxification process by the organism due to the formation of metallothioneins (MT), which are proteins that function as a detoxifying agent.

At present, it is unknown to what degree chemical pollutants are harmful sea turtle health, since the concentration of each metal vary between species and populations, due to the fact that several factors influence the pollutant load, such as habits, diet and the levels of pollutants found in its food, sex, age and physical condition, exposure time, as well as the local habitat characteristics and climatic conditions [40–44]. For this reason, the monitoring of heavy metals in sea turtles must be carried out for each species on a regional and population level.

Sea turtles are sentinel species due to their sensitivity to environmental pollutants which can be analysed in their tissues and reflect the bioaccumulation and behaviour of pollutants such as heavy metals in the environment in which they live. This allows for the identification of potential threats to the environment and health [45].

Regarding the Kemp's ridley turtle (*Lepidochelys kempii*), different authors point out that their population within the Gulf of Mexico is exposed to the heavy metal concentrations present in water and sediments, highlighting that the main sources of contamination in the area are due to large oil spills, such as IXTOC-I in 1979 and Deepwater Horizon in 2010, which increased the concentrations of Pb and other toxic elements, causing potential risks to biota. However, few studies [46] have been carried out on the levels of heavy metals in this sea turtle (**Table 3**), these studies observed that the concentrations of Pb increased with turtle size in a foraging area in Texas, USA, while in another foraging area in Louisiana, USA, Cu and Hg accumulated in higher concentration related to size. On the other hand, this relationship was not observed in the population of the southeast Atlantic. These regional differences were attributed to geographic differences, sources of contamination and levels of metals in the blue crab (*Callinectes sapidus*), the main component of the Kemp's ridley's diet.

These differences observed in Kemps ridley turtles and the interspecific variability of the pollutant load due to the factors described above, show the importance of periodically monitoring the levels of heavy metals in the Gulf of Mexico and in this sea turtle, which would expand knowledge about the levels of these pollutants in the Gulf of Mexico and the impact on the health of this species, contributing to better care and management in *L. kempii* sea turtle conservation programs.

#### **4.4 Molecular studies**

The study and analysis of nucleic acids in sea turtles has different approaches which depend on what type of nucleic acid is used to understand what, how and when to conduct molecular analysis. The application of genetics to improve species conservation efforts is an area with great potential, and there is a growing interest in this research.

All organisms or protein entities (such as viruses that contain DNA or RNA inside them) have different nucleic acid sequences (DNA or RNA). Variations are due to factors, such as differences between two individuals, which can be caused due to the time and space where they live, their biology, reproductive success, demographics, places and time of migrations and even natural selection. All the genetic information of each species is stored in its DNA; therefore, if its genome is analysed, it is possible to obtain this information for almost any evolutionary process. In conservation, the acquisition of this knowledge is important for identifying

*Natural History and Ecology of Mexico and Central America*

**126**

**SCL** 46.9 ± 5.0

NA 46.3 ± 7.1

65 ± 3.3 36.1 ± 7.4

7.4 ± 6.2 *F = Foraging. N = Nesting. NA = Not analysed.*

**Table 3.**

*\*Analysis performed on red blood cells. Mean (min-max) when the standard deviation is not reported.*

*Heavy metal concentrations reported in different areas (mean ± standard deviation,* μ*g g−1 wet weight) in L. kempii blood [46–48].*

F

91

0.01 ± 0.01

NA

0.01 ± 0.005

0.41 ± 0.11

0.03 ± 0.03

NA

6.71 ± 4.46

48

NA

N

18

0.06 ± 0.04

NA

0.01 ± 0.01

0.40 ± 0.09

0.05 ± 0.02

NA

22.70 ± 12.6

48

17.6 ± 7.4

F

18

0.01 ± 0.0092

NA

0.007 ± 0.05

0.470.06

0.02 ± 0.03

NA

3.9 ± 1.47

48

NA

F

106

0.018(0.0005–0.06)

NA

NA

0.52(0.21–1.3)

0.001(0.00–0.03)

NA

7.5(3.28–18.9)

47

16.6 ± 5.0

F

24

0.04 ± 0.04

**Weight**

**Area**

**n**

**Hg**

**As** 6.84 ± 1.98\*

0.02 ± 0.01\*

NA

**Cd**

**Cu**

**Pb** 0.01 ± 0.004\*

4.11 ± 1.83\*

NA

46

**Se**

**Zn**

**Author**

closely related individuals and mitigate inbreeding or exogamy and minimise the loss of genetic variation.

Although taxonomic studies based on morphological characteristics are used to classify individuals or species, molecular analyses are useful in studying sea turtles providing data on their evolution, populations, phylogeny, and how to implement conservation management plans based on molecular results. The study of DNA sequences can provide important information on sea turtle history and data related to their reproductive behaviour and ecology [46]. On the other hand, conservation objectives based on genetics present an opportunity to acquire a greater understanding of a population's status and management for genetic diversity preservation and prevent the persistent risks that affect populations. To better understand sea turtle species, studies should be directed towards those that provide precise data, such is the case of molecular markers.

Thus, molecular markers applied amongst other things to genetic studies, have relevance in countless studies in multiple species, their application in conservation provides information that helps in the understanding of evolutionary history, demography and ecology of endangered species. Information related to species distribution, biology and population dynamics is required to develop efficient and successful conservation strategies. Thanks to the development of molecular analyses and their application in sea turtle conservation, researchers have generated information that has contributed to species recovery [49]. Likewise, the application of molecular techniques can provide a breadth of information on different areas for conservation. However, many techniques present limitations which are subject to their correct use and development, including the correct selection of molecular markers. Therefore, we can consider that genetic or molecular markers are DNA sequences with known locations within a genome, a gene or in a non-coding region. They are generally directly or indirectly associated with the gene's function where they are located or the function of a contiguous gene. Some factors that must be taken into account in the use of molecular markers are the following: variation in the ability to detect differences between individuals, their application costs, ease of use, consistency, multiple capacities (evaluate several loci at the same time) and repetition.

These markers can be small sequences, such as polymorphisms (change or changes of one or more bases within a given sequence, in at least 1% of the population) of a single nucleotide (SNP, single nucleotide polymorphism) or long such as microsatellites [50]. Molecular markers are indispensable tools for determining genetic variation and biodiversity with a high degree of precision and reproducibility.

There are two possibilities within the study of molecular markers: nuclear DNA (nDNA) or in mitochondrial DNA (mDNA) markers. DNA from the mitochondrial genome provides information based on maternal lineage and population dispersion, which is used for analysis in molecular-phylogenetic studies, thanks to its ability to analyse evolution, since it evolves faster than nDNA, resulting in an accumulation of differences between nearby species. The mDNA can estimate gene flow and population history. The information found in the mDNA is conserved, with the absence of introns, short intragenic regions, and few duplications. Markers based on nDNA also called the nuclear genome, provide information on the genetic flow inherited by the male or males, as well as their polygamous reproduction habits with females from different nesting areas, in the same way resolving the paternity question for each nest.

Starting in the 90s, studies on sea turtles using different molecular markers notably increased. These studies have been crucial to increasing our understanding sea turtle ecology. Among the research carried out on sea turtles, one can find

**129**

*Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats*

species cataloguing and biodiversity inventories [51], identification of illegal sea turtle products, population structure and historical biogeography, phylogenies, female philopatry, male philopatry, multiple paternity, hybridisation, sex ratio [52], epigenetic factors, recombination processes, gene selection and drift that can gener-

For molecular studies of Kemp's ridley, we should consider different options and marker types. Before going into detail, we need to keep in mind that these studies require a methodical and systematised process, not only for the type of molecular analysis, but during the entire process, from the organisms capture, sampling, DNA extraction, amplification and sequencing and its bioinformatic analysis. Although there are large amounts of information on sea turtle species, molecular studies in the endemic kemps ridley turtle are limited. Therefore, here we will present a

Worldwide, biodiversity loss is accelerating due to multiple factors including land exploitation, excessive deforestation, drastic climate change, invasive species and emerging pathogens. Natural resource management focuses on accelerating the inventory of biological diversity, understanding its function and integrating its use in the sustainable development of human society. In this sense, due to the disciplinary crisis in conservation biology and thanks to the evolution of molecular information, a goal was established in which it is necessary to incorporate several technologies to accelerate, ensure and increase the precision of decision-making for conservation. One crucial approach in advancing conservation medicine was centralised database creation, such as the barcode database and DNA records. In 2003, Paul Hebert and his working group [53] at the University of Guelph, Canada, proposed implementing a coding sequence for cytochrome c oxidase subunit I (COI or CoxI) of the mitochondrial genome as a universal marker for animal species identification. The proposal was based on simulating the universal identifier as a "barcode" used to identify commercial products, their year of manufacture, batch, cost, or simple identification within a warehouse. Thanks to Hebert and his working group's novel work, in May 2004, the Consortium for the Barcode of Life (CBOL) was created, which currently has 130 organisations from 40 countries [54]. Cytochrome c oxidase subunit I (COI, or cox1) is a fragment of the mitochondrial multienzyme complex, which occurs as a transmembrane system related to the mitochondrial matrix. The region used for barcode generation is approximately 648 bp in length. In 2003, the COI gene was designated as standard "barcode" due to its absence of introns, low exposure to recombination, haploid genetic condition, variety of copies that allow easy DNA recovery, and high mutation rate that allows distinction between closely related species, being used as a universal marker for population genetic analysis, identification, phylogeographic studies and cataloguing of all species in all taxa of the animal kingdom. It presents a diversity of nucleotides in certain regions of the gene, a characteristic that allows the discrimination of

The use of this marker with a molecular taxonomic approach was carried out for species-level differentiation studies among 5 sea turtle species. The consumption of sea turtle products and by-products is an activity that often occurs in communities that live close to these species. The application of the "barcode" to identify illegal trafficking of sea turtle meat, eggs, carapace and other by-products helps counteract and combat these illegal activities. It is also useful in identifying stranded animals with a high level of decomposition or when traces of these species are present. Studies have used this mitochondrial fragment to identify samples of hawksbill sea turtle *Eretmochelys imbricata*. In this sense, the use of the mtDNA COI marker is useful for creating phylogenies and population dynamics and contributes directly to conservation actions for sea turtles [50, 56]. Advantages of this marker include the

*DOI: http://dx.doi.org/10.5772/intechopen.96655*

ate different genealogical histories.

probable closely related species [55].

general panorama of molecular studies in sea turtles.

#### *Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats DOI: http://dx.doi.org/10.5772/intechopen.96655*

species cataloguing and biodiversity inventories [51], identification of illegal sea turtle products, population structure and historical biogeography, phylogenies, female philopatry, male philopatry, multiple paternity, hybridisation, sex ratio [52], epigenetic factors, recombination processes, gene selection and drift that can generate different genealogical histories.

For molecular studies of Kemp's ridley, we should consider different options and marker types. Before going into detail, we need to keep in mind that these studies require a methodical and systematised process, not only for the type of molecular analysis, but during the entire process, from the organisms capture, sampling, DNA extraction, amplification and sequencing and its bioinformatic analysis. Although there are large amounts of information on sea turtle species, molecular studies in the endemic kemps ridley turtle are limited. Therefore, here we will present a general panorama of molecular studies in sea turtles.

Worldwide, biodiversity loss is accelerating due to multiple factors including land exploitation, excessive deforestation, drastic climate change, invasive species and emerging pathogens. Natural resource management focuses on accelerating the inventory of biological diversity, understanding its function and integrating its use in the sustainable development of human society. In this sense, due to the disciplinary crisis in conservation biology and thanks to the evolution of molecular information, a goal was established in which it is necessary to incorporate several technologies to accelerate, ensure and increase the precision of decision-making for conservation. One crucial approach in advancing conservation medicine was centralised database creation, such as the barcode database and DNA records.

In 2003, Paul Hebert and his working group [53] at the University of Guelph, Canada, proposed implementing a coding sequence for cytochrome c oxidase subunit I (COI or CoxI) of the mitochondrial genome as a universal marker for animal species identification. The proposal was based on simulating the universal identifier as a "barcode" used to identify commercial products, their year of manufacture, batch, cost, or simple identification within a warehouse. Thanks to Hebert and his working group's novel work, in May 2004, the Consortium for the Barcode of Life (CBOL) was created, which currently has 130 organisations from 40 countries [54].

Cytochrome c oxidase subunit I (COI, or cox1) is a fragment of the mitochondrial multienzyme complex, which occurs as a transmembrane system related to the mitochondrial matrix. The region used for barcode generation is approximately 648 bp in length. In 2003, the COI gene was designated as standard "barcode" due to its absence of introns, low exposure to recombination, haploid genetic condition, variety of copies that allow easy DNA recovery, and high mutation rate that allows distinction between closely related species, being used as a universal marker for population genetic analysis, identification, phylogeographic studies and cataloguing of all species in all taxa of the animal kingdom. It presents a diversity of nucleotides in certain regions of the gene, a characteristic that allows the discrimination of probable closely related species [55].

The use of this marker with a molecular taxonomic approach was carried out for species-level differentiation studies among 5 sea turtle species. The consumption of sea turtle products and by-products is an activity that often occurs in communities that live close to these species. The application of the "barcode" to identify illegal trafficking of sea turtle meat, eggs, carapace and other by-products helps counteract and combat these illegal activities. It is also useful in identifying stranded animals with a high level of decomposition or when traces of these species are present. Studies have used this mitochondrial fragment to identify samples of hawksbill sea turtle *Eretmochelys imbricata*. In this sense, the use of the mtDNA COI marker is useful for creating phylogenies and population dynamics and contributes directly to conservation actions for sea turtles [50, 56]. Advantages of this marker include the

*Natural History and Ecology of Mexico and Central America*

loss of genetic variation.

such is the case of molecular markers.

closely related individuals and mitigate inbreeding or exogamy and minimise the

Although taxonomic studies based on morphological characteristics are used to classify individuals or species, molecular analyses are useful in studying sea turtles providing data on their evolution, populations, phylogeny, and how to implement conservation management plans based on molecular results. The study of DNA sequences can provide important information on sea turtle history and data related to their reproductive behaviour and ecology [46]. On the other hand, conservation objectives based on genetics present an opportunity to acquire a greater understanding of a population's status and management for genetic diversity preservation and prevent the persistent risks that affect populations. To better understand sea turtle species, studies should be directed towards those that provide precise data,

Thus, molecular markers applied amongst other things to genetic studies, have relevance in countless studies in multiple species, their application in conservation provides information that helps in the understanding of evolutionary history, demography and ecology of endangered species. Information related to species distribution, biology and population dynamics is required to develop efficient and successful conservation strategies. Thanks to the development of molecular analyses and their application in sea turtle conservation, researchers have generated information that has contributed to species recovery [49]. Likewise, the application of molecular techniques can provide a breadth of information on different areas for conservation. However, many techniques present limitations which are subject to their correct use and development, including the correct selection of molecular markers. Therefore, we can consider that genetic or molecular markers are DNA sequences with known locations within a genome, a gene or in a non-coding region. They are generally directly or indirectly associated with the gene's function where they are located or the function of a contiguous gene. Some factors that must be taken into account in the use of molecular markers are the following: variation in the ability to detect differences between individuals, their application costs, ease of use, consistency, multiple capacities (evaluate several loci at the same time) and

These markers can be small sequences, such as polymorphisms (change or changes of one or more bases within a given sequence, in at least 1% of the population) of a single nucleotide (SNP, single nucleotide polymorphism) or long such as microsatellites [50]. Molecular markers are indispensable tools for determining genetic variation and biodiversity with a high degree of precision and

There are two possibilities within the study of molecular markers: nuclear DNA (nDNA) or in mitochondrial DNA (mDNA) markers. DNA from the mitochondrial genome provides information based on maternal lineage and population dispersion, which is used for analysis in molecular-phylogenetic studies, thanks to its ability to analyse evolution, since it evolves faster than nDNA, resulting in an accumulation of differences between nearby species. The mDNA can estimate gene flow and population history. The information found in the mDNA is conserved, with the absence of introns, short intragenic regions, and few duplications. Markers based on nDNA also called the nuclear genome, provide information on the genetic flow inherited by the male or males, as well as their polygamous reproduction habits with females from different nesting areas, in the same way resolving the paternity

Starting in the 90s, studies on sea turtles using different molecular markers notably increased. These studies have been crucial to increasing our understanding sea turtle ecology. Among the research carried out on sea turtles, one can find

**128**

repetition.

reproducibility.

question for each nest.

high level of barcode variation between specimens, which helps in the identification of cryptic species and thus its use in species identification, biodiversity and conservation studies. The barcode can also be used to facilitate species identification when this is difficult due to the organism ontogeny or due to only receiving an individual's remains. However, disadvantages exist when using this marker, such as the lack of clarity between the genetic separation values between intra- and interspecific divergence in the selected marker. The discovery of new species cannot be confined solely to a universal barcode, since this marker has errors in the genetic separation values for certain taxonomic groups.

Another commonly used marker is the control region in mDNA, which contains a displacement loop, known as the "D-loop", believed to be the most rapidly evolving region of the mitochondrial genome in most vertebrates. This structure contains most of the regulatory elements for the mitochondrial genome expression and is used to study intraspecific population structures. It has proven useful in the study of sea turtles, with molecular markers derived from the control region used to identify sea turtle natal origins and in the case of the loggerhead turtle (*Caretta caretta*) used to demonstrate their transpacific migration. In 1994, another study designed primers from the control region and amplified a 496 bp fragment for this control region in leatherback turtles [57].

The control region is a ubiquitous characteristic of vertebrate mitochondrial genomes, its name is due to its structure that consists of a triple chain of ~0.8-1 kb and is located between the genes that encode tRNAPro on the light strand (L -strand) and tRNAPhe on the heavy strand (H-strand). This morphology is created by the displacement of the parental H-strand by a DNA of 0.6–0.8 kb complementary to the L-strand. The control region measures between 880 and 1400 bp, and in some species, it can be greatly extended due to its repeated sequences. However, its reduced size and the increased understanding of its replication and transcription mechanisms, its sequence availability in many species, this region represents a good marker to analyse the non-coding regulatory genome to the evolution in the time of the establishment of mammals about 150 million years. In the late 1990s, Dutton et al. described the control region's use, in conjunction with recapture information, to test the philopatry hypothesis. Naro-Maciel et al. conducted a study using the control region as a marker for the DNA barcode, highlighting that although this region is useful in numerous species conservation studies, it does not meet all the criteria for use as a barcode sequence [50, 57].

One advantage of this genetic marker in sea turtle molecular studies is its high degree of variability. It is the most variable region of the mitochondrial and nuclear genome, evolving ten times faster than nDNA and can be used for species identification, even reaching the sub-species level. It degrades slower than nDNA and can be recovered from samples after long storage periods.

#### **5. Conclusion**

This chapter showed different stages of sea turtles, one in particular Kemp's ridley. Since that sea turtle has as a unique site to nest, it is important to understand what the real situation about the cycle of life, anthropogenic threats, genetic diversity, and pollution. Not only, for the turtles but for human beings. To see that, previous studies in sea turtles were describe in tissue samples such as carapace, kidney, liver, heart, etc. Another kind of used sample was blood. Blood as test tissue allows information on recent exposure to anthropogenic pollutants, it is inexpensive and easy to acquire. Also, it represents a relationship between the concentrations of heavy metals with other tissues, since the blood transports them through the

**131**

*Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats*

circulatory system to these. Biochemical analyzes could let us see if some population of this sea turtle is healthier than others o maybe understands if spills, such as

On the other hand, there are few molecular studies on these turtles, all of them in secondary nesting areas and with specimens from those places. This chapter would contribute to pointing out molecular studies in mtDNA sequences such as the COI gene, the control region, or in nuclear DNA microsatellite sequences. Which can reveal this species is important to the marine ecosystem conservancy, surely due to its location limited to a single geographical area, which is the Gulf of Mexico. Finally, for many years this species was unknown until brave and clever people decided to act and to protect them. They gave a legacy and showed how marvelous the nesting and hatching are. Now, it is a great opportunity to study with modern tools them and to understand if those sea turtles are healthy and strong to transmit their genes to the next generations of Kemp's ridley. In the end, we showed the state

This research was supported by SIP-20110067, 20161179, 20171851, 20196213, 20200840 and 20211061 projects from the Instituto Politécnico Nacional (IPN). The Apoyos económicos of Comisión de Operación y Fomento de Actividades Académicas (COFAA), Estímulos al Desempeño de los Investigadores (EDI), and Beca de estímulo institucional de formación de investigadores (BEIFI) from the IPN; and the National System of Researchers (SNI); the National Council of Science and Technology (CONACYT) provided fellowships and scholarships for MARL, CPLQ, FYCS, KAZF, VLS, and AAZN. Investigacion, Capacitacion y Soluciones Ambientales y Sociales A.C., Grupo tortuguero de las Californias A. C. We thank the entire community and Juan Martínez Ortíz of Rancho Nuevo, Aldama, Tamaulipas. Special thanks to Martha López Hernández, CONANP, Tamaulipas and Blanca Mónica Zapata Nájera, CONANP., and H. Hugo Acosta Sánchez-United Nations Development Programme-Comisión Nacional de Áreas Naturales Protegidas,

the one in 2010 in the Gulf of Mexico, impacts in this species.

of the art of the smallest, unique, and elusive sea turtle.

**Acknowledgements**

Ciudad Victoria, Tamaulipas, Mexico

The authors declare no conflict of interest.

**Conflict of interest**

*DOI: http://dx.doi.org/10.5772/intechopen.96655*

*Rediscovering Kemp's Ridley Sea Turtle (*Lepidochelys kempii*): Molecular Analysis and Threats DOI: http://dx.doi.org/10.5772/intechopen.96655*

circulatory system to these. Biochemical analyzes could let us see if some population of this sea turtle is healthier than others o maybe understands if spills, such as the one in 2010 in the Gulf of Mexico, impacts in this species.

On the other hand, there are few molecular studies on these turtles, all of them in secondary nesting areas and with specimens from those places. This chapter would contribute to pointing out molecular studies in mtDNA sequences such as the COI gene, the control region, or in nuclear DNA microsatellite sequences. Which can reveal this species is important to the marine ecosystem conservancy, surely due to its location limited to a single geographical area, which is the Gulf of Mexico. Finally, for many years this species was unknown until brave and clever people decided to act and to protect them. They gave a legacy and showed how marvelous the nesting and hatching are. Now, it is a great opportunity to study with modern tools them and to understand if those sea turtles are healthy and strong to transmit their genes to the next generations of Kemp's ridley. In the end, we showed the state of the art of the smallest, unique, and elusive sea turtle.
