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What is Scaevola?

Genus of flowering plant in family Goodeniaceae
130 tropical species
Originated in Australia

Scaevola plumieri

Scaevola taccada

Scaevola aemula

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Global Distribution of S. plumieri and S. taccada

S. plumieri

S. taccada

Puerto Rico

Vieques

Culebra

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Two Species of Scaevola Co-Inhabit Vieques, PR

Scaevola plumieri

Scaevola taccada

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Goals of This Research

1

Understand the genetic diversity and genetic structure of the S. plumieri and S. taccada on the island of Vieques

2

Identify if there is gene flow between the different populations and whether the species are in HWE

3

Understand if genetic diversity correlates with distance between populations of both S. plumieri and S. taccada

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Hypotheses

S. plumieri is well established and will have more genetic diversity and genetic structure than S. taccada.

There will be gene flow between beach populations in both species because they share pollinators.

Geographic distance will affect genetic structure.

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Is this a microsatellite?

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Understanding Microsatellites

Homozygotes

Heterozygotes

5’

3’

5’

3’

5’

3’

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

5

Forward Primer

Reverse Primer

Flanking Region

Repeats of 1-6 nucleotides

5-40 repeats

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Samples Collected & Kept in Silica Gel

Run PCR to amplify MSAT loci

DNA Extracted from Plant Tissue

Send plates for fragment analysis

Score MSAT Peaks on Geneious

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2

6

1

Playa Grande

2

12

4

Playa Navio

Punta Arena

Playuela

24

11

3

Pata Prieta

Playa Plata

S. plumieri (n=58)

S. taccada (n=21)

Population Sampling

11

3

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Hardy-Weinberg & Garza-Williamson

	S. plumieri			S. taccada
Beach	Expected Het.	Observed Het.	G-W Index	Expected Het.	Observed Het.	G-W Index
Playuela	0.50	0.32**	0.50	0.33	0.34	0.40
Punta Arena	0.46	0.50	0.65	MONOMORPHIC
Playa Grande	0.26	0.60	0.36	0.46	0.17	0.61
Playa Navio	0.26	0.33	0.72	0.29	0.50	0.67
Playa Plata	0.46	0.32**	0.54	0.29	0.70*	0.52
Pata Prieta	0.40	0.67	0.41

* = statistically significant (p < 0.05); # of asterisks correlate to # of sig. loci

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Where is Variation Happening?

Source of Variation	Percentage of Variation (%)
	S. plumieri	S. taccada
Among Groups	0	0
Among Populations Within Groups	13.67	26.06
Within Populations	32.30	23.69
Within Individuals	62.22	63.35
Fst Value	0.09	0.24

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Results: Mantel Test

Scaevola plumieri

Scaevola taccada

Distance Between Beaches

F_ST

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Conclusions

Hypothesis: S. plumieri is well established and will have more genetic diversity and genetic structure than S. taccada.

FALSE

More genetic diversity seen in S. taccada

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Conclusions

Hypothesis: There will be gene flow between beach populations in both species because they share pollinators.

There is low gene flow in S. plumieri and moderate gene flow in S. taccada.

Fst Value	0.09	0.24

S. plumieri	S. taccada

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Conclusions

Hypothesis: Geographic distance will affect genetic structure.

S. plumieri: FALSE S. taccada: TRUE

Scaevola taccada

Scaevola plumieri

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Future Directions

1

Apply additional primers to examine more MSAT loci & combine all previous data

2

Collect and analyze samples from the main island of Puerto Rico

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References

Images:

https://www.google.com/search?tbm=isch&q=scaevola+plumieri&*&imgrc=TixWO9CckRZYnM:&cad=h#imgrc=ETWakoc3Cu0HfM:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004837/

Additional images of Scaevola from Witherup Lab members!

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004837/

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DNA is Extracted from Lyophilized Leaf Samples

Preparation

Lysis

DNA Binding

Elution

Wash

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DNA is Amplified via PCR

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Samples Were Collected from Across Vieques

	Number of Samples From Each Research Site on Vieques, PR
	Playuela	Punta Arena	Playa Grande	Playa Navio	Pata Prieta	Playa Plata
S. plumieri	24	2	6	12	3	11
S. taccada	11	1	2	4	0	3

S. plumieri = 58 samples

S. taccada = 21 samples

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Variability Between Individuals

Individual 1

Individual 2

Individual 3

Individual 4

5’

3’

5’

3’

5’

3’

5’

3’

5’

3’

5’

3’

5’

3’

5’

1

2

3

4

1

2

3

4

1

2

3

1

2

3

4

5

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What is a Microsatellite Marker?

Flanking Region

5’

3’

1

2

3

4

1

2

3

4

3’

5’

Forward Primer

Reverse Primer

Flanking Region

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Using Microsatellite Markers to Study Genetic Diversity

Repeats of 1-6 nucleotides

5-40 repeats

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Homozygotes

Heterozygotes

5’

3’

5’

3’

5’

3’

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

5

Forward Primer

Reverse Primer

Flanking Region

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2

6

1

Playa Grande

2

12

4

Playa Navio

Punta Arena

Playuela

24

11

3

Pata Prieta

Playa Plata

11

3

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2

6

1

Playa Grande

2

12

4

Playa Navio

Punta Arena

Playuela

24

11

3

Pata Prieta

Playa Plata

Vieques Island

11

3

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Scaevola plumieri

Scaevola taccada

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	S. plumieri			S. taccada
Beach	Expected Het.	Observed Het.	G-W Index	Expected Het.	Observed Het.	G-W Index
Playuela	0.50	0.32**	0.50	0.33	0.34	0.40
Punta Arena	0.46	0.50	0.65	MONOMORPHIC
Playa Grande	0.26	0.60	0.36	0.46	0.17	0.61
Playa Navio	0.26	0.33	0.72	0.29	0.50	0.67
Playa Plata	0.46	0.32**	0.54	0.29	0.70*	0.52
Pata Prieta	0.40	0.67	0.41

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Source of Variation	Percentage of Variation (%)
	S. plumieri	S. taccada
Among Groups	0	0
Among Populations Within Groups	13.67	26.06
Within Populations	32.30	23.69
Within Individuals	62.22	63.35
Fst Value	0.09	0.24

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Scaevola plumieri

Scaevola taccada

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Scaevola plumieri

Scaevola taccada