Sex chromosomes and sex determination pathway dynamics in plant and animal models

Abstract

In this review, we discuss and compare data obtained from animal and plant models, focusing our attention on the mechanisms that affect sex linkage and changes in sex-determining pathways. Patterns in data across taxa suggest that sex bias and the dynamics that occurs within hybrid zones can play an important role in these processes that enable the spread of some otherwise handicapped genotypes. We discuss the data obtained from several main plant model species in the light of the patterns demonstrated in animal models. In several plant models, we discuss possible differences in the age of their sex-determining pathways and the age of their current sex chromosomes. We also address an open question: how can an X/A ratio based sex-determining system evolve from a sexdetermining system based on two genes on the Y chromosome that control two separate sex-determining pathways (for the control of gynoecium suppression and anther promotion)? Taking inspiration from the well described mechanisms involved in sex determination dynamics in animals, we suggest a hypothetical stepwise scenario of change of the plant sex-determining system based on two separate sex-determining pathways (for the control of gynoecium suppression and anther promotion) into the other sex-determining systems. We suppose that an intermediate step occurs before shift to X/A based sex determination. At that phase, sex determination in plants is still based on an active Y chromosome, although there exists already a connected control of both sex-determining pathways. We suggest that this connection is enabled by the existence of the genes that control sexual dimorphism in the vegetative state of plant development, and that, in some circumstances, these genes can become sexdetermining genes.

Sex determination in dioecious Mercurialis annua and its close diploid and polyploid relatives

“…; and s.d. with both genetic and environmental components (Bull, 1983;Werren and Beukeboom, 1998;Uller et al, 2007;Charlesworth and Mank, 2010;Janousek and Mrackova, 2010;Beukeboom and Perrin, 2014). Remarkably, quite different s.d.…”

“…mechanisms also vary among plants (Juarez and Banks, 1998;Ming et al, 2007;Janousek and Mrackova, 2010;Ming et al, 2011). Fully environmental s.d.…”

“…Multi-locus systems of s.d. are known from several animal species, including the swordtail fish Xiphophorus helleri (Woolcock et al, 2006), the European sea bass Dicentrarchus labrax (Vandeputte et al, 2007) and the housefly Musca domestica (Dubendorfer et al, 2002;Kozielska et al, 2006), but M. annua is cited as the only plant species known to display such a system (Dellaporta and Calderonurrea, 1993;Grant et al, 1994;Ainsworth, 2000;Janousek and Mrackova, 2010). The discovery of the single sexlinked SCAR marker OPB01-1562 (that is, a Sequence Characterized Amplified Region of 1562 bp in length) in dioecious M. annua (Khadka et al, 2002), which was found in all males tested but not in females, casts doubt on the three-locus model.…”

Patterns and Mechanisms of Evolutionary Transitions between Genetic Sex-Determining Systems

“…Some species use a specific environmental cue (e.g., temperature, photoperiod, or population density) as the primary sex-determining signal (environmental sex determination; ESD), whereas others rely on various types of genetic sex determination (GSD), including male or female heterogamety, haplodiploidy or multilocus sex-determining mechanisms (Bull 1983;Marshall Graves 2008;Janousek and Mrackova 2010). In addition, sex determination can depend on epigenetic factors such as imprinting or maternal gene products deposited in the egg (Verhulst et al 2010a).…”

Comparative Analysis of Gene Expression by Microarray Analysis of Male and Female Flowers ofAsparagus officinalis

“…1) There are many different sex-determination mechanisms in plants, ranging from the XY system common to many species to a completely autosomal determination system. [2][3][4][5][6] Knowledge of sex determination in plants remains limited, although much progress has been made in the study of other aspects of dioecious plants, such as sex-linked genes over the past years. [7][8][9][10][11][12][13] Among dioecious plants, garden asparagus (Asparagus officinalis) belongs to the family Liliaceae, with 2n ¼ 2x ¼ 20 chromosomes and a haploid genome size of 1,323 Mb.…”