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Related Concept Videos

Genome Size and the Evolution of New Genes03:21

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
Genome Size and the Evolution of New Genes03:21

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
Comparing Mitochondrial, Chloroplast, and Prokaryotic Genomes02:16

Comparing Mitochondrial, Chloroplast, and Prokaryotic Genomes

The present-day mitochondrial and chloroplast genomes have retained some of the characteristics of their ancestral prokaryotes and also have acquired new attributes during their evolution within eukaryotic cells. Like prokaryotic genomes, mitochondrial and chloroplast genomes neither bind with histone-like proteins nor show complex packaging into chromosome-like structures, as observed in eukaryotes. Unlike mitotic cell divisions observed in eukaryotic cells, mitochondria and chloroplasts...
Lampbrush Chromosomes01:51

Lampbrush Chromosomes

In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
Hybrid Zones02:29

Hybrid Zones

Hybrid zones are narrow regions where two closely related species interact, mate, and produce hybrids. Relative to either parent species, hybrids may possess distinct phenotypic or genetic differences that impact their survival and reproductive success. The genetic variances introduced by hybridization influence species diversity and speciation processes within the hybrid zone.
Cell Size01:22

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (μm)and are considerably smaller than most eukaryotic cells. The smallest bacteria are 0.1 μm in diameter—about a thousand times smaller than eukaryotic cells, which typically range from 10-100 μm.
Surface Area
Cells can take in nutrients and water via diffusion through the plasma membrane itself or through specific channels in the membrane. The area of the membrane surrounding the cells limits the...

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Related Experiment Video

Updated: May 25, 2026

Generation of Transgenic Hydra by Embryo Microinjection
09:10

Generation of Transgenic Hydra by Embryo Microinjection

Published on: September 11, 2014

Genome size differences in Hyalella cryptic species.

Roland Vergilino1, Kaven Dionne, Christian Nozais

  • 1Département de biologie, chimie et géographie et Centre d'études nordiques, Université du Québec à Rimouski, Rimouski, Canada. rvergilino@gmail.com

Genome
|January 24, 2012
PubMed
Summary

Genome size varies between Hyalella azteca ecomorphs. Large ecomorph species possess significantly larger genome sizes than small ecomorph species, potentially reflecting ecological adaptations in this amphipod complex.

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Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans
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Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans

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Last Updated: May 25, 2026

Generation of Transgenic Hydra by Embryo Microinjection
09:10

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Published on: September 11, 2014

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans
08:24

Size Matters: Measurement of Capsule Diameter in Cryptococcus neoformans

Published on: February 27, 2018

Area of Science:

  • Ecology
  • Evolutionary Biology
  • Genomics

Background:

  • The Hyalella azteca complex comprises numerous cryptic amphipod species in American freshwater ecosystems.
  • Two distinct ecomorphs, small and large, have repeatedly evolved within this complex.
  • Limited phenotypic traits exist to distinguish between these cryptic species.

Purpose of the Study:

  • To investigate genome size variations among co-occurring Hyalella azteca complex species in a Canadian boreal lake.
  • To utilize flow cytometry to quantify nuclear DNA content and assess interspecies genome size differences.

Main Methods:

  • Nuclear DNA content was measured in 50 individuals representing six COI haplotypes.
  • These haplotypes corresponded to four provisional species within the Hyalella azteca complex.
  • Flow cytometry was employed for precise genome size estimation.

Main Results:

  • Species belonging to the large ecomorph exhibited significantly greater C-values (genome size) compared to those in the small ecomorph.
  • Minor genome size variations were observed among species within the small ecomorph.
  • Significant differences in genome size were detected between the large and small ecomorphs.

Conclusions:

  • Genome size is a differentiating factor between large and small ecomorphs of the Hyalella azteca complex.
  • Observed genome size differences may correlate with ecological and physiological variations among species.
  • This study provides insights into the evolutionary divergence and speciation within the Hyalella azteca complex.