Paris Veltsos Research

peduncle of male plant with leaves

Mercurialis annua

Enter the name for this tabbed section: Identification of the Y chromosome of Mercurialis annua

Identification of the Y chromosome of Mercurialis annua

A BAC containing a Y-specific marker has been sequenced with PacBio technology. The assembled sequence has been annotated. I am in the process of sequencing exons and introns from the predicted genes in an attempt to identify sex-specific PCR products and characterise sequences from the X and Y chromosomes.

The long term goal is to identify the sex-determining gene, which may require chromosome walking through the BAC library.

Another aim is to obtain sequences from the closely related polyploid lineages/species that have males (M. huetti and M. canariensis) to determine whether they share the same sex-determining region.

In collaboration with Guillaume Cossard.
Example of male specific PCR (4 first wells).
Enter the name for this tabbed section: Cytogenetics
sterile plants for agrobacterium infection

Mercurialis cytogenetics

plant hairy roots, a source of chromosomes
Mercurialis cytogenetics
We are developing hairy root cultures in Mercurialis lineages. These are a good source of mitotic chromosomes.

We will use FISH and GISH to characterise the state of the Y chromosome for example the accumulation of transposable elements, but also to confirm the hypothesised parental species that are involved in polyploidisation in the genus. Y-specific markers could also be developed to confirm whether the different ploidy lineages use the same sex chromosomes, as well as the number of those chromosomes in the polyploids.

The project is in collaboration with the lab of Boris Vyskot and Roman Hobza.
hairy roots
Newly developping hairy roots, a good source of chromosomes.
diploid M. annua chromosome spread
Diploid M. annua chromosomes.
Diploid M. annua chromosomes labelled with a transposable element (red) and 5S rDNA (green).
Enter the name for this tabbed section: Characterisation of YY plants

Characterisation of YY plants

We will assess the level of Y chromosome degeneration by growing individuals containing two Y chromosomes, generated by mating hormonally feminised males with normal males.

Phenotypic differences of the males containing two Y chromosomes would indicate that the Y is significantly different from the X, and possible developmental anomalies or fitness consequences would suggest gene expression differences between the X and the Y, potential Y gene degeneration or the accumulation of recessive deleterious mutations in the non-recombining region of the Y chromosome.

We will identify the YY individuals from their XY brothers by quantification of a Y marker through RT-PCR. We will then collect and analyse phenotypic measures of the XY and YY plants, such as pollen count, flower number, fertility and root to shoot ratio.

This is a summer student project in co-supervised with Guillaume Cossard.
A potential YY individual