Dr Susan Mazer, University of California, Santa Barbara Symposium: What is Local? Genetics & Plant Selection in the Urban Context. (Tuesday, May 23, 2006, American Museum of Natural History)

1. Genetics 101: Genetic differentiation in the age of ecological restoration Susan J. Mazer Department of Ecology, Evolution & Marine Biology University of California, Santa Barbara [email_address]

2. Genetics 101: Genetic differentiation in the age of ecological restoration Susan J. Mazer Department of Ecology, Evolution & Marine Biology University of California, Santa Barbara [email_address]

4. Up and running: common vocabulary Population genetic processes Genetic phenomena Ecological considerations

5. Up and running: common vocabulary Inheritance in a nutshell Local adaptation Genetic differentiation Genetic drift Founder effect Genetic swamping Population genetic processes Genetic phenomena Ecological considerations

6. Up and running: common vocabulary Inheritance in a nutshell Local adaptation Genetic differentiation Genetic drift Founder effect Genetic swamping Ecotype Heterosis & “hybrid vigor” Inbreeding depression Outbreeding depression Hybrid breakdown Population genetic processes Genetic phenomena Ecological considerations

7. Up and running: common vocabulary Inheritance in a nutshell Local adaptation Genetic differentiation Genetic drift Founder effect Genetic swamping Ecotype Heterosis & “hybrid vigor” Inbreeding depression Outbreeding depression Hybrid breakdown Phenology Pollen limitation Climate change Population genetic processes Genetic phenomena Ecological considerations

30. Up and running: common vocabulary Inheritance in a nutshell Local adaptation Genetic differentiation Genetic drift Founder effect Genetic swamping Population genetic processes Genetic phenomena Ecological considerations Ecotype Heterosis & “hybrid vigor” Inbreeding depression Outbreeding depression Hybrid breakdown

34. Ecotypes: example Ecotypes of Sida fallax and their hybrids in Hawai’i. A. Beach ecotype. B. Mountain ecotype. C, D, and E: hybrid leaves. F: Beach flower. G. Hybrid flower. H. Mountain flower. Beach ecotype, prostrate habit with pubescent leaves Mountain ecotype, erect shrub with hairless leaves Beach ecotype Mountain ecotype Hybrid leaves

54. Mechanism of Hybrid Breakdown beteen Genotypes Participating in Restoration Effort Resident Population Under Restoration Source Population of Introduced Genotypes

55. If local adaptation has occurred, resident and source populations will be genetically distinct and homozygous for alternative alleles of the same gene Resident Population Under Restoration Source Population of Introduced Genotypes aa BB CC dd EE AA bb cc DD ee

56. Restoration Phase I: Introduction of genotypes from a chosen “source” population Resident Population Under Restoration Source Population of Introduced Genotypes aa BB CC dd EE AA bb cc DD ee

57. aa BB CC dd EE AA bb cc DD ee F1 Hybrids produced Following Introduction aA Bb Cc dD Ee Restoration Step II: Mating between genotypes of resident and source populations….What is the fate of these hybrids? Resident Population Under Restoration Source Population of Introduced Genotypes

58. aa BB CC dd EE AA bb cc DD ee Genotypes Participating in Restoration Effort: What is the fate of these hybrids? F1 Hybrids produced Following Introduction aA Bb Cc dD Ee Resident Population Under Restoration Source Population of Introduced Genotypes

59. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Hybrid Breakdown

60. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Hybrid Breakdown Assume: Parent 1 is a resident at restoration site or adapted to its environment.

61. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Hybrid Breakdown Assume: Parent 1 is a resident at restoration site or adapted to its environment. Assume: Parent 2 is adapted to an alternative environment and genetically distinct from Parent 1.

62. Parent 2 Parent 1 Hybrid Breakdown X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F1 hybrid F2 generation following recombination Homozygous diploid parents F1 hybrids will have a full complement of alleles from each parent, so they may function well at restoration site

63. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F1 hybrid F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Following sexual reproduction, F2 hybrid offspring will regain homozygosity at many loci Hybrid Breakdown

64. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F1 hybrid F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Where F2s are homozygous for genes from Parent 2, they may not be well adapted to Parent 1’s environment Hybrid Breakdown

65. X aa BB CC dd EE AA bb cc DD ee aA Bb Cc dD Ee F1 hybrid F2 generation following recombination Homozygous diploid parents Parent 2 Parent 1 Hybrid Breakdown

66. Possible Outcome of Hybridization between Resident and Introduced Genotypes F1 generation exhibits hybrid vigor. After the first generation of hybridization, population mean fitness declines as homozygotes are reconstituted Mean Population Fitness Residents Hybrids Residents + Hybrids

67. Possible Outcome of Hybridization between Resident and Introduced Genotypes F1 generation exhibits genetic swampling or dilution. After the first generation of hybridization, population mean fitness increases as resident homozygotes are reconstituted. Mean Population Fitness Residents Hybrids Residents + Hybrids

68. Mean Population Fitness Mean Population Fitness Possible Outcomes of Hybridization between Resident and Introduced Genotypes After 1st generation, population mean fitness declines as adaptive combinations are shuffled Magnitude of decline will depend on strength of natural selection Residents Hybrids Residents + Hybrids

69. Up and running: common vocabulary Inheritance in a nutshell Local adaptation Genetic differentiation Genetic drift Founder effect Genetic swamping Population genetic processes Genetic phenomena Ecological considerations Ecotype Heterosis & “hybrid vigor” Inbreeding depression Outbreeding depression Hybrid breakdown Phenology Pollen limitation Climate change

75. Short-term (more or less immediate) consequences: Long-term consequences: Synthesis: Consequences of inappropriate source selection

76. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance Long-term consequences: Synthesis: Consequences of inappropriate source selection

77. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Long-term consequences: Synthesis: Consequences of inappropriate source selection

78. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Synthesis: Consequences of inappropriate source selection

79. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Hybrid breakdown poor performance of F2 and subsequent generations Synthesis: Consequences of inappropriate source selection

80. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Hybrid breakdown poor performance of F2 and subsequent generations Potential for phenological mismatch Synthesis: Consequences of inappropriate source selection

81. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Hybrid breakdown poor performance of F2 and subsequent generations Potential for phenological mismatch Potential failure to be pollinated Synthesis: Consequences of inappropriate source selection

82. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Hybrid breakdown poor performance of F2 and subsequent generations Potential for phenological mismatch Potential failure to be pollinated Pollen-stigma incompatibilities Synthesis: Consequences of inappropriate source selection

83. Short-term (more or less immediate) consequences: Genetic swamping or dilution reduction in mean population performance High mortality reduced population size Reduced genetic variation Long-term consequences: Hybrid breakdown poor performance of F2 and subsequent generations Potential for phenological mismatch Potential failure to be pollinated Pollen-stigma incompatibilities Inability to adapt to climate change (due to limited genetic variation). Synthesis: Consequences of inappropriate source selection

85. Surviving stand of Nassella pulchra (a native perennial bunchgrass)

86. Nassella pulchra

87. Bromus carinatus

88. Elymus glaucus

89. Genetics 101: Genetic differentiation in the age of ecological restoration Susan J. Mazer Department of Ecology, Evolution & Marine Biology University of California, Santa Barbara [email_address]