Significant Variations Between Chinese and American Chestnuts

Unexpected Genetic Rift: Significant Variations Between Chinese and American Chestnuts Hetrosolutions

Unexpected Genetic Rift: Significant Variations Between Chinese and American Chestnuts…

A new study in Scientific Reports uncovers considerable discrepancies in the nucleolus organizing region. This discrepancy calls into question presumptions regarding their suitability for hybridization to produce resistance to blight.


Possible effects on blight resistance and restoration of American chestnuts.

It turns out that there are differences between the chromosomes of American and Chinese chestnuts. The discovery, which was reported in a Scientific Reports paper today (January 15), has significant ramifications for anyone hoping to hybridize Chinese and American chestnuts to provide American chestnuts resistance to blight.
“This is an unprecedented finding in the field of plant cytology,” says Nurul Faridi, a Forest Service geneticist and primary author of the study.
Without using genetic engineering, traditional backcross breeding involves hybridizing two species in an effort to get the best possible combination of features from both. Only in cases where the chromosomes of the two species are compatible may backcross breeding be successful.
People have thought that there is considerable compatibility between the two species since Chinese-American chestnut hybrids are viable. However, the two species’ NORs differ significantly, according to the latest study.
Unexpected Genetic Rift: Significant Variations Between Chinese and American Chestnuts Hetrosolutions
The chestnut tree is a hardwood deciduous tree that produces edible chestnuts in addition to its enormous, serrated leaves. It is endemic to several parts of the world, including Europe, Asia, and North America. It is a member of the genus Castanea. Chestnut trees are prized for their nuts and their timber, which can reach remarkable heights. These trees have been essential to human history because they have produced timber for a variety of uses and have provided food.
  • The Function of the NOR
Every cell in plants and animals has a NOR. It contains the genetic information needed to create ribosomes, which are the molecular organelles that assemble proteins necessary for life.

Near the end of a specific chromosome’s short arm is where it found. Both species have it, but the Chinese chestnut has more of it than the other because it has a lot of heterochromatin, a form of DNA that makes up around 25% of the chromosome. The researchers were taken aback by the shape and makeup of this DNA, which is transcriptionally dormant, highly condensed, and devoid of gene content.

The American chestnut satellite, on the other hand, is little and seems to be euchromatic. The transcription activity of DNA is present in euchromatic areas.

Exposing the Finding

Using a UV filter, a dye that attaches to DNA, and a specialized microscope, Faridi initially observed a small pair of Chinese chestnut chromosomes exhibiting unusually strong fluorescence.

Faridi examined the finding in further detail using a method known as fluorescent in situ hybridization (FISH).

According to Faridi, “our excellent FISH images provide unmistakable evidence of this unique DNA arrangement.” “These images demonstrate the dynamic nature of genetic material; they are more than just pictures.”

Significant Variations Between Chinese and American Chestnuts

Chromosome satellite for both species (Chinese chestnut on the left, American chestnut on the right). These are composed of chromatin, a mixture of DNA and proteins, just like all other chromosomes. There are various chromatin kinds. The Chinese chestnut’s brilliant blue tip denotes heterochromatic DNA, whereas the tip’s paler purple hue could be euchromatic DNA. The American chestnut satellite region as a whole seems to be euchromatic. Credit: Photo by Nurul Faridi from the USDA Forest Service

The Path Ahead

For more analysis, the researchers will employ a method known as oligonucleotide FISH. short. Targeted DNA probes obtained from DNA sequencing are used in oligo-FISH. With the complete genomes of Chinese and American chestnuts sequenced, oligo-FISH will enable the researchers to perform in-depth genetic analyses that will identify minute genomic variations. Given that the approach can identify the parent gene of a hybrid, it is particularly valuable for research on hybrids.

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