Polyploidy Part 3. Patterns in Nature: Speciation

 Polyploidy is whole genome duplication, when all the chromosomes and so, all the genes, of an organism double. In plants, it is very common; easily 3/4 of plants are polyploid. 

an Oenothera

Because polyploidy is a genetic effect that takes place inside the cell's nucleus, it is not casually observed. But botanists discovered polyploidy as soon as they had microscopes to look at the contents of the nucleus and when they tried crossing polyploids and got results that didn't make sense based on diploid genetics. (Diploid = 2 copies of the genome, polyploidy = numbers over 2, like 3, 4, and 6  see previous posts in this series link link). Study of polyploidy began in the early 1900s.

Plant Story--Catnip, Nepeta cataria, a Well-Known Weedy Herb

 Catnip, Nepeta cataria, is one of the better-known little herbs because it is a drug for cats. Cats respond to catnip for about 15 minutes, with distinctive behaviors from rubbing on their faces and rolling in it to grooming and salivating. Young kittens do not respond and some adult cats never do. On the other hand, the response is widespread among cats of all kinds, lions, tigers, cheetahs, lynx, pumas and so on, but not dogs or rabbits or rats or other groups of animals. Since cats are common pets, people provide or grow catnip for them, with the result that catnip is known to many people.

catnip, Nepeta cataria

April in Tokyo

Here is a photo album of pictures from Tokyo in April. Beautiful spring flowers.

The photos are from April 2017 but if you hurry, you could still get there to see what it is like in 2024: 

Classical Japanese design

Polyploidy Part 2. And Crop Plants

Polyploidy is whole genome duplication, where all the chromosomes double. Animals rarely survive major chromosome changes, but plants usually do, leading to aspects of plant genetics that are quite different from animals. 

strawberry, Fragaria ananassa

Even though you cannot easily spot a polyploid by looking at it, polyploidy is not obscure. Many common, important plants are polyploid, for example bread wheat (Triticum aestivum), white potatoes (Solanum tuberosum), coffee (Coffea arabica), sweet potatoes (Ipomoea batatas), strawberries (Fragaria x ananassa) and cotton (Gossypium tomentosum). Researchers estimate that 75% of all plants, and likewise, 75% of crops, are polyploids.  

Still Winter? More Flowers!

It is still winter for me. The ground is brown and cold. Oh, I can see a trace of green in the lawn and a new shoot or two on the iris, if I look carefully.  My snowdrops and crocuses are out of the ground, but not yet flowering. So, here are photos of summer flowers for cheer. Just a few more months...

Annual sunflower, the cultivated Ukrainian sunflower, Helianthus annuus

Polyploidy, Multiple Copies of the Genome. Part 1. Basics

One peculiar characteristic of plants, not much shared by animals, is polyploidy, multiple copies of all the chromosomes. In plants and animals, DNA, the genetic material, is bound up in protein-wrapped bodies called chromosomes. Organisms have several to many chromosomes, usually as pairs. For animals, each species has a characteristic number--humans 23 pairs, dogs 39 pairs--with very little variation. One of the ways that plants are DIFFERENT is that chromosome number can vary a lot, between species but also between plants of the same species growing next to each other.  

carrots, flowering

Plant Story--Sambucus nigra, Black Elderberry Uses and Folklore

Since prehistory times, humans all over the world have collected black elderberries, the fruit of black elder (Sambucus nigra, viburnum family, Viburnaceae) (see previous post: link). The plant has been used medicinally for that long as well. In addition, it grows into a nice tree, 20, sometimes 30, feet tall, with useful wood. The leaves were used as insect repellents. Folklore abounded, some protecting the plant, some considering it accursed. My herbal, traditional, and folklore books have long sections on elder. Here is a selection of what they say.

black elderberries, Sambucus nigra