TY  - JOUR
A1  - Kappel, Christian
A1  - Illing, Nicola
A1  - Huu, Cuong Nguyen
A1  - Barger, Nichole N.
A1  - Cramer, Michael D.
A1  - Lenhard, Michael
A1  - Midgley, Jeremy J.
T1  - Fairy circles in Namibia are assembled from genetically distinct grasses
JF  - Communications biology
N2  - Fairy circles are striking regularly sized and spaced, bare circles surrounded by Stipagrostis grasses that occur over thousands of square kilometres in Namibia. The mechanisms explaining their origin, shape, persistence and regularity remain controversial. One hypothesis for the formation of vegetation rings is based on the centrifugal expansion of a single individual grass plant, via clonal growth and die-back in the centre. Clonality could explain FC origin, shape and long-term persistence as well as their regularity, if one clone competes with adjacent clones. Here, we show that for virtually all tested fairy circles the periphery is not exclusively made up of genetically identical grasses, but these peripheral grasses belong to more than one unrelated genet. These results do not support a clonal explanation for fairy circles. Lack of clonality implies that a biological reason for their origin, shape and regularity must emerge from competition between near neighbor individuals within each fairy circle. Such lack of clonality also suggests a mismatch between longevity of fairy circles versus their constituent plants. Furthermore, our findings of lack of clonality have implications for some models of spatial patterning of fairy circles that are based on self-organization. Christian Kappel et al. examine the genetic composition of fairy circles, regular circular patterns of grasses in the Namib Desert, using ddRAD-seq. They find that these grasses are made up of multiple unrelated genets rather than genetically identical grasses, suggesting non-clonality.
Y1  - 2020
U6  - https://doi.org/10.1038/s42003-020-01431-0
SN  - 2399-3642
VL  - 3
IS  - 1
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Huu, Cuong Nguyen
A1  - Keller, Barbara
A1  - Conti, Elena
A1  - Kappel, Christian
A1  - Lenhard, Michael
T1  - Supergene evolution via stepwise duplications and neofunctionalization of a floral-organ identity gene
JF  - Proceedings of the National Academy of Sciences of the United States of America (PNAS)
N2  - Heterostyly represents a fascinating adaptation to promote outbreeding in plants that evolved multiple times independently. While L-morph individuals form flowers with long styles, short anthers, and small pollen grains, S-morph individuals have flowers with short styles, long anthers, and large pollen grains. The difference between the morphs is controlled by an S-locus "supergene" consisting of several distinct genes that determine different traits of the syndrome and are held together, because recombination between them is suppressed. In Primula, the S locus is a roughly 300-kb hemizygous region containing five predicted genes. However, with one exception, their roles remain unclear, as does the evolutionary buildup of the S locus. Here we demonstrate that the MADS-box GLOBOSA2 (GLO2) gene at the S locus determines anther position. In Primula forbesii S-morph plants, GLO2 promotes growth by cell expansion in the fused tube of petals and stamen filaments beneath the anther insertion point; by contrast, neither pollen size nor male incompatibility is affected by GLO2 activity. The paralogue GLO1, from which GLO2 arose by duplication, has maintained the ancestral B-class function in specifying petal and stamen identity, indicating that GLO2 underwent neofunctionalization, likely at the level of the encoded protein. Genetic mapping and phylogenetic analysis indicate that the duplications giving rise to the style-length-determining gene CYP734A50 and to GLO2 occurred sequentially, with the CYP734A50 duplication likely the first. Together these results provide the most detailed insight into the assembly of a plant supergene yet and have important implications for the evolution of heterostyly.
KW  - heterostyly
KW  - Primula
KW  - supergene
KW  - gene duplication
KW  - neofunctionalization
Y1  - 2020
U6  - https://doi.org/10.1073/pnas.2006296117
SN  - 0027-8424
VL  - 117
IS  - 37
SP  - 23148
EP  - 23157
PB  - National Academy of Sciences
CY  - Washington
ER  -