What is a polyploid series found in many plant genera What d

What is a polyploid series, found in many plant genera? What does it signify about evolutionary history?

Solution

Polyploid is the presence of more than two chromosome sets in an organism and polyploidy refers to the numerical change in the whole set of chromosomes.

Eukaryotic organisms, mostly animals, are diploid and produce haploid gametes. Plants which have two alternating generations, often are polyploid. There are some organisms which possess only one set of chromosomes and said to be monoploid.

In plant genera, there also exist a unique feature, known as polyploidy series. It refers to the group of species or related forms which possess different multiples of the same monoploid set of chromosomes. Polyploidy series is most evident in Angiosperms, and it is considered that 30-70% of angiosperms are polyploid in nature.

For example, in the species of coffee plants, there exist chromosome sets such as 22, 44, 66 and 88. This suggests that the original monoploid set was n = 11. Also, the domestic wheat of today is a hexaploid, consisting of 42 chromosomes. Therefore the ancestral variety would have n = 7 chromosomes.

Significance about evolutionary history