Non-Mendelian transmission of apomixis in maize-Tripsacum hybrids caused by a transmission ratio distortion
Grimanelli, D.
Non-Mendelian transmission of apomixis in maize-Tripsacum hybrids caused by a transmission ratio distortion - 1998 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0018-067X
Apomixis is a mode of asexual reproduction through seeds. The apomictic process bypasses both meiosis and egg cell fertilization: producing offspring that are exact genetic replicas of the mother plant. In the Tripsacum agamic complex, all polyploids reproduce through the diplosporous type of apomixis, and diploids are sexual. In this paper, molecular markers linked with diplospory were used to analyse various generations of maize-Tripsacum hybrids and backcross derivatives and to derive a model for the inheritance of diplosporous reproduction. The results suggest that the gene or genes controlling apomixis in Tripsacum are linked with a segregation distorter-type system promoting the elimination of the apomixis alleles when transmitted through haploid gametes. Hence, this model offers an explanation of the relationship between apomixis and polyploidy. The evolutionary importance of this mechanism, which protects the diploid level from being invaded by apomixis, is discussed.
English
Apomixis
Genetic inheritance
Heritability
Maize
Reproductive performance
Research projects
Tripsacum
Zea mays
Plant breeding
ORSTOM CIMMYT
Non-Mendelian transmission of apomixis in maize-Tripsacum hybrids caused by a transmission ratio distortion - 1998 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0018-067X
Apomixis is a mode of asexual reproduction through seeds. The apomictic process bypasses both meiosis and egg cell fertilization: producing offspring that are exact genetic replicas of the mother plant. In the Tripsacum agamic complex, all polyploids reproduce through the diplosporous type of apomixis, and diploids are sexual. In this paper, molecular markers linked with diplospory were used to analyse various generations of maize-Tripsacum hybrids and backcross derivatives and to derive a model for the inheritance of diplosporous reproduction. The results suggest that the gene or genes controlling apomixis in Tripsacum are linked with a segregation distorter-type system promoting the elimination of the apomixis alleles when transmitted through haploid gametes. Hence, this model offers an explanation of the relationship between apomixis and polyploidy. The evolutionary importance of this mechanism, which protects the diploid level from being invaded by apomixis, is discussed.
English
Apomixis
Genetic inheritance
Heritability
Maize
Reproductive performance
Research projects
Tripsacum
Zea mays
Plant breeding
ORSTOM CIMMYT