THE IMPORTANCE OF PANGENOMES
Why is genome sequencing important? DNA is the blueprint for almost all life on Earth. It carries the genetic instructions that tell an organism’s body how to develop, grow, and function. Changes in DNA can affect organisms—sometimes the changes don’t cause any changes in the organism, sometimes they cause problems, like disease, and sometimes they cause benefits, like a plant being resistant to drought. Identifying and understanding changes in DNA is crucial for solving many of today's challenges, such as diseases, food security, and climate change. DNA sequencing was very expensive and time-consuming in the early days of genetics and genomics research. As such, scientists created single reference genomes—generated using one individual from a species—to represent the entire species. Now that genetic sequencing is more commonplace and affordable, scientists are leveraging a new tool to examine gene changes: PANGENOMES .
What is a pangenome? REFERENCE GENOMES are used as a point of comparison when identifying disease- or trait-causing DNA changes, comparing sequence similarity in genes across species. With advances in sequencing technology, scientists can now sequence more individuals within a species faster and more affordably. Using the growing number of unique genomes, scientists have begun constructing collections of genomes, called pangenomes, to help represent the full genetic diversity of a species. PANGENOMES present all of the genes and DNA sequences within a species. They are created by sequencing many mem- bers of a species and comparing their genomes. Pangenomes show a species' complete genome information as well as its genetic diversity. How is a pangenome different from other large-scale sequencing projects? Pangenomes aim to capture the full spectrum of genetic diversity within a species. Key differences include: Breadth of Variation: Pangenomes go beyond common variation to capture rare and unique sequences. They can identify tricky structural variants, like duplications, deletions, insertions, and translocations. Inclusivity: Pangenomes aim to represent a wider range of human populations, ensuring a more complete and accurate understanding of our genetic makeup. Data Type: Pangenomes analyze whole-genome sequences, providing a more comprehensive view of genetic information than projects focused on specific types of variations.
Organism 1
Unique
Dispensable
Dispensable
CORE
Organism 2
Organism 3
Unique
Unique
PANGENOME
Within a pangenome, the CORE GENOME includes the genes and genetic changes that are shared by all of the individuals in a species. The DISPENSABLE GENOME is the portion of the genome that is only in a subset of individuals or is unique to one individual. This contains, for example, genes that have been selected by adapting to certain environmental conditions.
1 individual of blended ancestry
70%
Original human genome reference sequence
19 individuals mostly of European ancestry
30%
Collection of human genome reference sequences
PANGENOME
T
C
G
T
-SNV
-SNV
-SNV
-SNV
AGGT
CCCACTC
GTAGCCGCA
GTACATC ACGTGGC
C
T
G
A
Individual human genome reference sequences
ATCGCG
16
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