SCIENCE LAB SCENICS* : GOOD GENES

 

A FLOWER with a supersize sex chromosome : A vast majority of plants are hermaphrodites, with both male and female reproductive parts, capable of reproducing without a member of another sex nearby.

'' It makes sense if you are an organism that can't run around and find mates,'' said Deborah Charlesworth, a population geneticist at the University of Edinburgh.

But some plants have taken a different approach. They have evolved sex chromosomes,  the bits of DNA that make individual plants either male or female. In that club are organisms like the ginkgo, whose females produce stinky fruits, while males are stink-free.

Some of these species are stranger yet : Their sex chromosomes are bizarrely outsize. The diminutive white campion plant, for instance,  packs a Y chromosome bigger than the entire genome of the puffer fish or the fruit fly.

In the journal Science, researchers have published a full sequence of the white campion's Y chromosome.

In the paper, researchers used a new technique on the white campion's Y. Then, they sequenced the sex chromosome of the male plants that exhibited mutations, and pinpointed genes playing different roles in making them male.

Some genes suppressed female traits. Others encouraged male ones, influencing processes like flower development and pollen production.

This may explain why the campion's Y chromosome is so large. Preserving these genes and others like them might have taken priority over keeping the chromosome compact, said Ms. Charlesworth.

Much of the Y's bulk is made up of pieces of DNA that tend to duplicate themselves.

The World Students Society thanks Veronique Greenwood.