JUNTTI LAB
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​Why Study Cichlids?
 
A variety of social systems among cichlids. There are over 2000 species of cichlids, found predominantly in the Rift Valley lakes of East Africa. These species are ideal model species because they have robust social behaviors and a tremendous variety of social systems, including monogamy and polygamy; parental care by females, males, or both; aggressive territoriality and relative gregariousness. They communicate via auditory, chemical, and visual means that differ across species. In fact, these cues are crucial for females as they choose a mate, and this sexual selection for specific characteristics likely contributed to the explosive radiation of species. Several dozen cichlid species genomes have been sequenced, and falling sequencing costs enable additional genomes to be sequenced at will. Most work focuses on the cichlid Astatotilapia burtoni, a species from Lake Tanganyika with a sequenced genome that we study in the lab. We will also exploit the variety of cichlid species with social systems that are not found in any traditional laboratory model organism to gain insights into complex social behaviors.

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Cooperative parenting among monogamous Neolamprologous brichardi cichlids
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Territorial dominance displays between two Astatotilapia burtoni males
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Parental behavior: mouth brooding of embryos
Many technologies are applicable to cichlid fish. Many approaches used in more traditional model organisms can also be used in cichlids. Recent genetic advances have opened a world of possibilities where genetic sequences can be determined and manipulated quickly and easily. ​Some of the technologies we have used are: 
  • In situ hybridization & Immunohistochemistry
  • Active neuron profiling (immediate-early genes & phospho-S6)
  • Behavior tracking and analysis
  • Electrophysiology
  • Pharmacology
  • Gene modification with CRISPR
  • High-throughput transcriptome sequencing (RNA-seq)
  • Chromatin profiling
  • Genome sequencing
  • Evolutionary genetic comparisons
As new technologies become available, we will adapt them to the cichlid system to probe the basis of social behavior.
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We transgenically labeled Gonadotropin releasing hormone (GnRH1) neurons with EGFP, enabling cell type specific electrophysiological recording.
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Electrophysiological recordings from pairs of GnRH1 neurons allowed us to detect electrical connections between the cells.
Recently, we've developed a fluorescent line using Tol2, Tuba:GCaMP for calcium imaging. This line allows each neuron throughout the fish, including in the brain and olfactory epithelium, to express GCaMP via the ​a-tubulin promotor. The images above show the basal level of fluorescence in the brain in five day old larvae on the right, and a three day old larval brain on the left.
 In addtition to our Tuba:GCaMP​ line, we've also developed a Tyrosinase knockout line with CRISPR, resulting in eumelanin-lacking fish. A knockout male is pictured above. Coupled with our GCaMP line, these lines allow for real time calcium imaging. On the right, our Tyrosinase male is being chased by a wild type male in dominant coloration.
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Astatotilapia burtoni exhibit a stereotyped, complex spawning routine involving male courtship, circling, egg laying, fertilization and the initiation of parental (mouth brooding) behavior. This routine provides a great system to dissect with genetic tools because it is innate and sensitive to hormonal factors. Bottom: Quantitative analysis of spawning behavior in A. burtoni. Circle diameter is proportional to number of behaviors; arrow weight is proportional to number of transitions between behaviors. Prostaglandin F signaling is necessary and sufficient for the initiation of pecking and circling by females during spawning.
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In situ hybridization. Cells of the preoptic area express the prostaglandin F receptor mRNA (left), and are active during sexual behavior, as assayed by cfos mRNA labeling (right).
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Automated tracking of cichlid fry enables us to watch their trajectories and automatically infer behaviors. This may permit rapid phenotyping of CRISPR-induced mutants, for example.
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  • Home
  • Why Cichlids?
  • Publications
  • Resources
  • Join
  • Cichlid Genome Manipulation
    • CRISPR/Cas9
    • Transgenics
    • Microinjections
    • Community discussion
  • About
    • Lab Members
    • Contact