Featured Research

from universities, journals, and other organizations

Chromosomes' big picture: Similarities found in genomes across multiple species; Platypus still out of place

Date:
July 11, 2011
Source:
Kansas State University
Summary:
By mapping various genomes onto an X-Y axis, a team of researchers has found that Charles Darwin and a fruit fly -- among other organisms -- have a lot in common genetically. The researchers found that the chromosome sizes within each eukaryotic species are actually similar rather than drastically different as previously believed. They also found that the chromosomes of these different organisms share a similar distribution pattern.

In a new study, researchers found that the chromosome sizes within each eukaryotic species are actually similar rather than drastically different as previously believed. They also found that the chromosomes of these different organisms share a similar distribution pattern.
Credit: Image courtesy of Kansas State University

By mapping various genomes onto an X-Y axis, a team comprised mostly of Kansas State University researchers has found that Charles Darwin and a fruit fly -- among other organisms -- have a lot in common genetically.

Their discovery, "Chromosome Size in Diploid Eukaryotic Species Centers on the Average Length with a Conserved Boundary," was recently published in the journal Molecular Biology and Evolution. It details a project that compared 886 chromosomes in 68 random species of eukaryotes -- organisms whose cells contain a nucleus and are enclosed by cellular membranes. The researchers found that the chromosome sizes within each eukaryotic species are actually similar rather than drastically different as previously believed. They also found that the chromosomes of these different organisms share a similar distribution pattern.

Because chromosomes are the genetic building blocks for an organism and its traits, the information will be beneficial to understanding the core components of biological evolution -- especially in genetics and genome evolution, said Jianming Yu, associate professor of agronomy at Kansas State University. With this data, scientists can now better predict the evolutionary adaptations of an organism.

"Basically what this all means is that if the chromosome number of a species can be given, the relative sizes of all the chromosomes can instantly be known," Yu said. "Also, if you tell me the genome size in the chromosome base pair, I can tell you the base pair length of each chromosome."

According to Yu, the most surprising finding is the extremely consistent distribution pattern of the chromosomes, a result from comparing the full sets of chromosomes -- called genomes -- of the 68 random eukaryotes. The team found that nearly every genome perfectly formed an S-curve of ascending chromosomal lengths when placed on a standardized X-Y axis. That meant the genome from a species of rice expressed the same pattern as the genome from a species of maize, sorghum, fruit fly, dog, chimpanzee, etc.

In order to reach these findings, though, the team started by comparing various genomes of species from multiple organisms, looking for similarities. The genomes selected were from eukaryotes; prokaryotes -- organisms like bacteria that contain no cell nucleus; vertebrates -- organisms with a spine; invertebrates -- organisms without a spine, such as insects; vascular plants -- plants that can transport food and material throughout their tissue; and unicellular organisms.

From there the team looked specifically at the chromosomes of 68 random eukaryote genomes. This amounted to observing 886 chromosomes, 22 of which were human autosomes -- any chromosome other than a sex chromosome. The sex chromosomes of each species were omitted because of their vastly different evolutionary history from other chromosomes, Yu said.

The researchers placed each fully sequenced eukaryote genome onto an X-Y axis, hoping to find similarities between the various organisms. To help generalize the vast amount of information, the X-Y axis graph was standardized with each species.

"It eliminated a scale effect and made it possible to compare a species with several dozen chromosomes to a species with much fewer chromosomes," said Xianran Li, research associate in agronomy.

That's when the team noticed the shockingly consistent distribution pattern.

"We could not believe this the first time the plot was generated," said Chengsong Zhu, research associate in agronomy.

The only genomes that deviated from forming an S-curve were that of the platypus -- an organism that contains characteristics of birds, reptiles, mammals, amphibians and fish -- and those of birds. Birds are unique because in addition to their usual chromosome sequences, they contain one additional set of minichromosome sequences, according to Zhongwei Lin, research associate in agronomy.

By finding normal distribution in nearly all of the genomes they used, geneticists can now say that if a species has a particular number of chromosomes, the chromosomes have to be distributed in this order because it's dictated by the laws of mitosis, meiosis and cell division, according to Guihua Bai, adjunct professor of agronomy at Kansas State University and research geneticist of the U.S. Department of Agriculture-Agricultural Research Service.

"The integration of biology and statistics holds enormous promises to gain insights from genomic data and life processes," said Min Zhang, associate professor of statistics from Purdue University and a co-author of the paper.

"We're in the genomic age, where sequencers and computers are constantly running and completing new genome sequences every day," Yu said. "We're expecting this information can help when it comes to finding similarities in those genomes. This type of broad analysis across species, taxonomic and disciplinary boundaries is really exciting in terms of discovering fundamental principles out of teeming genomic data."

The project was supported with funding from Kansas State University's Targeted Excellence Program, National Science Foundation, National Institutes of Health, U.S. Department of Defense and a seed grant through Purdue University's Discovery Park.

Other Kansas State University researchers include Yun Wu, research assistant in agronomy, and Weixing Song, assistant professor of statistics. Also collaborating on the study were four other biologists and statisticians from Purdue University, University of Minnesota and Cornell University.


Story Source:

The above story is based on materials provided by Kansas State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. X. Li, C. Zhu, Z. Lin, Y. Wu, D. Zhang, G. Bai, W. Song, J. Ma, G. J. Muehlbauer, M. J. Scanlon, M. Zhang, J. Yu. Chromosome Size in Diploid Eukaryotic Species Centers on the Average Length with a Conserved Boundary. Molecular Biology and Evolution, 2011; DOI: 10.1093/molbev/msr011

Cite This Page:

Kansas State University. "Chromosomes' big picture: Similarities found in genomes across multiple species; Platypus still out of place." ScienceDaily. ScienceDaily, 11 July 2011. <www.sciencedaily.com/releases/2011/07/110706113450.htm>.
Kansas State University. (2011, July 11). Chromosomes' big picture: Similarities found in genomes across multiple species; Platypus still out of place. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/07/110706113450.htm
Kansas State University. "Chromosomes' big picture: Similarities found in genomes across multiple species; Platypus still out of place." ScienceDaily. www.sciencedaily.com/releases/2011/07/110706113450.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins