**3.2 Genetic diversity**

*Natural History and Ecology of Mexico and Central America*

considered, obtaining similar results.

P > 0.05) (**Figure 4**).

P < 0.05) (**Figure 4**).

CH, GA, AN, and SA. If it was impossible to measure the adult plants' height and diameter because they had a subterranean stem, only the number of leaves was

The average height for non-reproductive individuals was 23.4 cm ± 3.4, with a maximum average height of 52.2 cm and the lowest of 14.5 cm. For reproductive plants, the maximum recorded height was 56.3 cm, and the lowest was 9.5 cm, with an average of 28.8 cm ± 8.3. However, the ANOVA showed that there are differences among means in plant height between localities (df = 8; F = 5.428; P < 0.001) and between categories of reproductive status in localities (df = 8; F = 4.992; P < 0.05), but not between categories of reproductive status in each locality (df = 1; F = 2.633;

The average stem diameter was 12.2 cm ± 2.5 in non-breeding individuals, with a width of 23.6 cm to 15.0 cm (**Figure 4A**), and in reproductive individuals, the average was 16.5 cm ± 4.4 with a maximum of 31.2 cm and a minimum of 5.5 cm. The ANOVA showed that there are no differences in the mean diameter between localities (df = 8; F = 1627; P > 0.05) or between categories of reproductive status in each locality (df = 1; F = 2848; P > 0.05), but there are differences between the categories of reproductive status of individuals in the localities (df = 8; F = 4034;

*Size of* Dioon edule *plants (± SE) in each location. (A) Non reproductive and, (B) reproductive. Different* 

**102**

**Figure 4.**

*letters mean significant differences (Tukey <0.05).*

Only three of the first seven proposed were amplified, ED9, TOM5, and CAP5. All the loci were polymorphic, but the population AN have the lowest proportion of polymorphic loci (33.33%) in the seedlings (**Table 3**). The average number of alleles per locus was 3.66; in the seedling stage, the lowest value corresponds to Los AN (1.33) (**Table 3**). There were no unique alleles within the adult stage. However, in the juvenile and seedling, four and three unique alleles were found, respectively, and ED9 was the locus that presented the highest number of unique alleles.


**Table 3.**

*Genetic diversity index for five* Dioon edule *populations in San Luis Potosi, Mexico.*


**Table 4.**

**105**

**Table 5.**

*The Endangered Species* Dioon edule *in the Sierra Madre Oriental in San Luis Potosí…*

The average heterozygosity (Ho) was 0.207. The highest value was in the seedlings in PO with 0.333, and the lowest in the seedlings in PO (Ho = 0.0), and the adult stage in CH (0.048) (**Table 3**). For the expected Heterozygosity, the average was 0.504 and the highest value was 0.634 in the juvenile category for the PO

In the populations, only two loci resulted in Hardy–Weinberg equilibrium (H-W), ED9 in the populations of RN, PO, and AN, and TOM5 in the population of RN (**Table 4**). In the seedlings, the ED9 locus resulted in H-W balance in the populations of CH, PO, and SA and TOM5 resulted in balance in RN. The loci CAP5 in PO and SA populations and ED9 in SA, were monomorphic, and CAP5 in PO and SA populations and ED9 in SA. In the juveniles, ED9 resulted in H-W equilibrium in all populations. However, in adults, this same locus resulted in equilibrium in most

The AMOVA showed that the categories' differences are explained by the genetic variation between individuals for all populations and each age category (Seedlings = 50%; juveniles: 59%; adults: 62%: Total: 58%) (**Table 4**). The inbreeding coefficient (FIS) generally shows a deficiency of heterozygotes in all popula-

The fixation index (Fst) indicates a moderate differentiation in all populations, as well as in the age categories (Fst ≈ 0.11–0.115). The populations that share more alleles are CH and PO located in the south of the study area (Fst = 0.057; p = 0.006); those that share fewer alleles are PO and SA also in the south (Fst = 0.265; p = 0.001) (**Table 5**). The seedlings have a high genetic differentiation between pairs of populations (Fst > 0.26; p < 0.05), while in the juveniles, the differentiation is moderate (Fst > 0.110; p < 0.05), and in adults from moderate to

**Life cycle stage Source df SS MS VAR %** Seedling BP 4 20.63 5.16 0.27 26%

Juvenile BP 4 12.30 3.08 0.11 11%

Adult BP 4 11.53 2.88 0.10 11%

Total BP 4 31.21 7.80 0.15 15%

*Analysis of molecular variance (AMOVA) based on three microsatellite loci for five* Dioon edule *populations in San Luis Potosi, Mexico. BP = between populations; BI = between individuals; WI = within individuals.*

BI 30 39.21 1.31 0.52 50% WI 35 9.00 0.26 0.26 24% Total 69 68.84 1.06 100%

BI 30 44.93 1.50 0.60 59% WI 35 10.50 0.30 0.30 30% Total 69 67.73 1.01 100%

BI 30 41.86 1.40 0.57 62% WI 35 8.50 0.24 0.24 26% Total 69 61.89 0.93 100%

BI 100 142.33 1.42 0.58 58% WI 105 28.00 0.27 0.27 27% Total 209 201.54 1 100%

*DOI: http://dx.doi.org/10.5772/intechopen.96372*

populations except CH (**Table 4**).

high (Fst > 1.15; p < 0.05).

tions and age categories (Fis ≈ 0.666–0.708) (**Table 5**).

locality.

*Hardy–Weinberg equilibrium test for three microsatellite loci for five* Dioon edule *populations in San Luis Potosi, Mexico.*

*The Endangered Species* Dioon edule *in the Sierra Madre Oriental in San Luis Potosí… DOI: http://dx.doi.org/10.5772/intechopen.96372*

The average heterozygosity (Ho) was 0.207. The highest value was in the seedlings in PO with 0.333, and the lowest in the seedlings in PO (Ho = 0.0), and the adult stage in CH (0.048) (**Table 3**). For the expected Heterozygosity, the average was 0.504 and the highest value was 0.634 in the juvenile category for the PO locality.

In the populations, only two loci resulted in Hardy–Weinberg equilibrium (H-W), ED9 in the populations of RN, PO, and AN, and TOM5 in the population of RN (**Table 4**). In the seedlings, the ED9 locus resulted in H-W balance in the populations of CH, PO, and SA and TOM5 resulted in balance in RN. The loci CAP5 in PO and SA populations and ED9 in SA, were monomorphic, and CAP5 in PO and SA populations and ED9 in SA. In the juveniles, ED9 resulted in H-W equilibrium in all populations. However, in adults, this same locus resulted in equilibrium in most populations except CH (**Table 4**).

The AMOVA showed that the categories' differences are explained by the genetic variation between individuals for all populations and each age category (Seedlings = 50%; juveniles: 59%; adults: 62%: Total: 58%) (**Table 4**). The inbreeding coefficient (FIS) generally shows a deficiency of heterozygotes in all populations and age categories (Fis ≈ 0.666–0.708) (**Table 5**).

The fixation index (Fst) indicates a moderate differentiation in all populations, as well as in the age categories (Fst ≈ 0.11–0.115). The populations that share more alleles are CH and PO located in the south of the study area (Fst = 0.057; p = 0.006); those that share fewer alleles are PO and SA also in the south (Fst = 0.265; p = 0.001) (**Table 5**). The seedlings have a high genetic differentiation between pairs of populations (Fst > 0.26; p < 0.05), while in the juveniles, the differentiation is moderate (Fst > 0.110; p < 0.05), and in adults from moderate to high (Fst > 1.15; p < 0.05).


#### **Table 5.**

*Natural History and Ecology of Mexico and Central America*

**104**

**Location**

CH

CAP5

ED9 TOM5 CAP5

ED9 TOM5 CAP5

ED9 TOM5 CAP5

ED9 TOM5 CAP5

ED9 TOM5

> **Table 4.**

14.00 *Hardy–Weinberg equilibrium test for three microsatellite loci for five* Dioon edule *populations in San Luis Potosi, Mexico.*

0.003

7.00

0.008

7.00

0.008

42.00

0.000

3.34

0.343

24.67

0.055

8.89

0.180

31.50

0.008

6.00

0.014

monomorphic

SA

7.00

0.008

14.00

0.003

14.00

6.00

0.014

18.00

0.000

0.003

63.00

0.000

monomorphic monomorphic

AN

21.00

0.002

7.00 4.00 12.00

0.285

5.06

0.537

15.04

0.449

0.046

6.00

0.014

11.00

0.001

0.008

7.00

0.008

63.00

0.000

5.07

0.535

2.29

0.514

7.88

0.247

10.25

0.115

monomorphic

7.00

0.008

7.00

0.008

21.00

0.000

PO

0.04

0.839

monomorphic

14.67

0.023

9.75

0.136

9.64

0.140

monomorphic

16.26 0.01

0.911

0.092

7.00

0.008

14.00

0.003

7.00

0.008

42.00

0.000

RN

14.00

0.003

7.00

0.008

7.00

0.008

42.00

0.000

11.33

0.332

14.04

0.171

15.52

0.017

38.85

0.001

7.00

0.008

6.07

0.108

7.00

0.008

20.04

0.000

**Locus**

**Seedling**

> χ**<sup>2</sup>**

**P-value**

χ**<sup>2</sup>**

**P-value**

χ**<sup>2</sup>**

**P-value**

χ**<sup>2</sup>**

**P-value**

**Juvenile**

**Adult**

**Total**

*Analysis of molecular variance (AMOVA) based on three microsatellite loci for five* Dioon edule *populations in San Luis Potosi, Mexico. BP = between populations; BI = between individuals; WI = within individuals.*
