Biologists find the long and short of it when it comes to chromosomes

February 27, 2019

A team of biologists has uncovered a mechanism that determines faithful inheritance of short chromosomes during the reproductive process. The discovery, reported in the journal Nature Communications, elucidates a key aspect of inheritance--deviation from which can lead to infertility, miscarriages, or birth defects such as Down syndrome.

The research centers on how short chromosomes can secure a genetic exchange. Genetic exchanges are critical for chromosome inheritance, but are in limited supply.

How short chromosomes ensure a genetic exchange is of great interest to scientists given the vulnerability of short chromosomes.

"Short chromosomes are at a higher risk for errors that can lead to genetic afflictions because of their innate short lengths and therefore have less material for genetic exchange," explains Viji Subramanian, a post-doctoral researcher at New York University and the paper's lead author. "However, these chromosomes acquire extra help to create a high density of genetic exchanges--but it hadn't been understood as to how short chromosomes received this assistance."

To explore this question, the researchers, who also included Andreas Hochwagen, an associate professor in NYU's Department of Biology, studied this process in yeast--a model organism that shares many fundamental processes of chromosome inheritance with humans.

Overall, they found that vast regions near the ends of both short and long chromosomes are inherently primed for a high density of genetic exchanges--the scientists labeled these end-adjacent regions (EARs). Of particular note, a high density of genetic exchanges in EARs is conserved in several organisms, including birds and humans.

Significantly, the researchers noted that EARs are of similar size on all chromosomes. This means that EARs only occupy a limited fraction of long chromosomes but almost the entirety of short chromosomes. This difference drives up the density of genetic exchanges, specifically on short chromosomes, and does so without cells having to directly measure chromosome lengths.
-end-
The paper's other authors included Tovah Markowitz, an NYU doctoral student at the time of the research, and Luis Vale-Silva, an NYU post-doctoral researcher at the time of the study, as well as Xuan Zhu and Scott Keeney of Memorial Sloan Kettering Cancer Center, Nancy Hollingsworth of Stony Brook University, and Pedro San-Segundo of the University of Salamanca.

This research was supported by grants from the National Institutes of Health (R01 GM111715, R35 GM118092, R01 GM050717, and P30 CA008748)

New York University

Related Chromosomes Articles from Brightsurf:

Cancer's dangerous renovations to our chromosomes revealed
Cancer remodels the architecture of our chromosomes so the disease can take hold and spread, new research reveals.

Y chromosomes of Neandertals and Denisovans now sequenced
An international research team led by Martin Petr and Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has determined Y chromosome sequences of three Neandertals and two Denisovans.

Female chromosomes offer resilience to Alzheimer's
Women live longer than men with Alzheimer's because their sex chromosomes give them genetic protection from the ravages of the disease.

New protein complex gets chromosomes sorted
Researchers from the University of Tsukuba have identified a novel protein complex that regulates Aurora B localization to ensure that chromosomes are correctly separated during cell division.

Breaking up is hard to do (especially for sex chromosomes)
A team of scientists at the Sloan Kettering Institute has discovered how the X and Y chromosomes find one another, break, and recombine during meiosis even though they have little in common.

Exchange of arms between chromosomes using molecular scissors
The CRISPR/Cas molecular scissors work like a fine surgical instrument and can be used to modify genetic information in plants.

How small chromosomes compete with big ones for a cell's attention
Scientists at the Sloan Kettering Institute have solved the puzzle of how small chromosomes ensure that they aren't skipped over during meiosis, the process that makes sperm and egg.

GPS for chromosomes: Reorganization of the genome during development
The spatial arrangement of genetic material within the cell nucleus plays an important role in the development of an organism.

Extra chromosomes in cancers can be good or bad
Extra copies of chromosomes are typical in cancerous tumor cells, but researchers taking a closer look find that some extra copies promote cancer growth while others actually inhibit cancer metastasis.

X marks the spot: recombination in structurally distinct chromosomes
A recent study from the laboratory of Stowers Investigator Scott Hawley, PhD, has revealed more details about how the synaptonemal complex performs its job, including some surprising subtleties in function.

Read More: Chromosomes News and Chromosomes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.