Outbreeding depression in the fernAsplenium ruta-murariaL.: Evidence from enzyme electrophoresis, meiotic irregularities and reduced spore viability

Abstract

Asphiurn rub-rnuraria is a mainly inbEding, highly specialized, rock or wall inhabiting, autotetraploid fern. Enzyme electrzhoresis combined with cytological investigations and s p s e measurements r e v e g that outbr7eding deprssion occurs in natural po75ations when two different genotypes cross. Crossing results insregularities in m e i s and reduced s p z e fertility. Two h y p s e s e s are formulated to explain this phenomenon. The first hypo5esis suggests a multiple origin of autopolyploids and assumes that long distance dispersal by spores mixes very distant and locally a d s t e d genoGes. Thus, the consequence is the observed o u t b a d % depression. The second hypotJhesis assumes that i n b s d i n g has a very high adaptive value in this ecologicay specialized, autoprnloid species. This fact and strong selection for r e s r meiosis have led to fuiy fertile inbred lines, which are capable of founding populdtons by single spores. Crzsing of two genetically different lines may disturb the control of pairing in meiosis and thus c a g e outbreeding depression. k

Development of primer sets for PCR amplification of the PgiC gene in ferns

“…Interestingly, the contrasted mating systems between diploids and polyploids are in good agreement with theoretical considerations regarding the evolution of inbreeding (Lande and Schemske 1985;Hedrick 1987). At this stage, however, information regarding the mating systems of polyploid species is still scarce (Watano 1988;Soltis and Soltis 1990;Watano and Masuyama 1991;Schneller 1996). It therefore remains uncertain whether the contrasting mating systems observed represent an accurate evolutional trend in homosporous pteridophytes.…”

Sampling bias in geographic and environmental space and its effect on the predictive power of species distribution models

“…Higher colonization ability may be related to the potential of single spore colonization, reduced variability of small isolated populations, and reduced impact of inbreeding depression (Holderegger & Schneller, 1994;Schneller, 1996;Vogel et al, 1999;Suter et al, 2000). However, diploids with mixed mating systems observed for example in A. scolopendrium, with outcrossing when possible and occasional self-fertilization when needed, can also have increased colonization potential (Wubs et al, 2010).…”

Do malaria parasites mate non-randomly in the mosquito midgut?

“…Outcrossing depression has been observed in a wide variety of organisms (Waser & Price, 1994 ;Schneller, 1996 ;Schierup & Christiansen, 1996 ; for a review see Templeton, 1994). Outcrossing may break up favourable gene complexes and reduce fitness in organisms that characteristically have high levels of inbreeding.…”