Contrasting evolutionary forces in the Arabidopsis thaliana floral developmental pathway.
The floral developmental pathway in Arabidopsis thaliana is composed of several interacting regulatory genes, including the inflorescence architecture gene TERMINAL FLOWER1 (TFL1), the floral meristem identity genes LEAFY (LFY), APETALA1 (AP1), and CAULIFLOWER (CAL), and the floral organ identity genes APETALA3 (AP3) and PISTILLATA (PI). Molecular population genetic analyses of these different genes indicate that the coding regions of AP3 and PI, as well as AP1 and CAL, share similar levels and patterns of nucleotide diversity. In contrast, the coding regions of TFL1 and LFY display a significant reduction in nucleotide variation, suggesting that these sequences have been subjected to a recent adaptive sweep. Moreover, the promoter of TFL1, unlike its coding region, displays high levels of diversity organized into two distinct haplogroups that appear to be maintained by selection. These results suggest that patterns of molecular evolution differ among regulatory genes in this developmental pathway, with the earlier acting genes exhibiting evidence of adaptive evolution.
Olsen
Kenneth M
KM
Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695, USA.
Womack
Andrew
A
Garrett
Ashley R
AR
Suddith
Jane I
JI
Purugganan
Michael D
MD
D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D005075:Biological Evolution; D014644:Genetic Variation; D018398:Homeodomain Proteins / Q000235:genetics; D026161:MADS Domain Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D014157:Transcription Factors
C091535:AP1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C074747:LFY protein, Arabidopsis; D026161:MADS Domain Proteins; D010940:Plant Proteins; C102864:TFL1 protein, Arabidopsis; D014157:Transcription Factors