Zebra Fish New Discovered Sex Hormone (Secretoneurin)
What is Sex Hormone?
Hormones, such as
estrogen, testosterone or any of a class of
steroid hormones that is produced especially by the
ovaries, testes, or any part of the brain which affects the growth and functions of
the reproductive organs or involved in the development of secondary sex
characteristics in any animal or plant.
estrogen, testosterone or any of a class of
steroid hormones that is produced especially by the
ovaries, testes, or any part of the brain which affects the growth and functions of
the reproductive organs or involved in the development of secondary sex
characteristics in any animal or plant.
Secretogranin-2 occurrence
Kim Mitchell et
al-2020 of university of Ottawa, capital of Canada altered
secretogranin-2 is a protein encoded by secretogranin genes through specific
mutation technique (using gene-editing technology) and found that it affected reproduction
process in fish (female and male zebrafish unable to breed.
Importance
of Secretogranin-2
of Secretogranin-2
Secretogranin-2 is vital for the normal working of brain cells and other cells that secrete hormones to switch
body functions such as growth and reproduction.
body functions such as growth and reproduction.
Key
role of Secretoneurin
role of Secretoneurin
However, secretogranin-2 can get
sliced up by distinctive enzymes that one small fragment called secretoneurin (33-amino
acid neuropeptide) is a key player for stimulating sexual function in the Danio rerio (zebrafish) a model organism
carp fish.
sliced up by distinctive enzymes that one small fragment called secretoneurin (33-amino
acid neuropeptide) is a key player for stimulating sexual function in the Danio rerio (zebrafish) a model organism
carp fish.
Secretogranin-2 in Human
In human, secretogranin-2 is
produced by a gene named as SCG2 gene and is involved in wrapping or
categorization of peptide hormones and neuropeptides into secretory vesicles.
produced by a gene named as SCG2 gene and is involved in wrapping or
categorization of peptide hormones and neuropeptides into secretory vesicles.
Secretogranin-2 in zebrafish
Kim Mitchell et al., 2020 reported
secretoneurin strictly reduced their sexual behavior
in zebrafish.
secretoneurin strictly reduced their sexual behavior
in zebrafish.
Effects of Secretogranin-2 on Sexual
Mature fish look
ordinary, but when both sexes are put together, they practically ignore each
other as per researcher work published with titled “Targeted mutation of
secretogranin-2 disrupts sexual behavior…….. PNAS, in press; doi:
10.1073/pnas.2002004117”.
ordinary, but when both sexes are put together, they practically ignore each
other as per researcher work published with titled “Targeted mutation of
secretogranin-2 disrupts sexual behavior…….. PNAS, in press; doi:
10.1073/pnas.2002004117”.
Why Danio rerio (zebrafish) as a model
organism?
organism?
- Since zebrafish eggs are fertilized and developed outside fish body, it is an ideal model organism for studying early development.
- Zebrafish has a genetic structure similar to that of humans. They share 70% of the genes with us.
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| Zebra-fish Model organism |
Important
Feature of Model organism
Feature of Model organism
- A model organism is a
species that has been extensively studied, generally because it is easy to
maintain and reproduce in the laboratory and has particular experimental
benefits. - Model organisms are
non-human species used in the laboratory to help scientists understand biological
processes.
Ethical
value for a model organism such as zebrafish
•The body can prevent
the transmission of disease from one species to another, thereby reducing fish
mortality.
• As compared to invertebrates model organisms, they
have more genes than other animals. As delicate organisms, special care must
be taken when handling them.
value for a model organism such as zebrafish
•The body can prevent
the transmission of disease from one species to another, thereby reducing fish
mortality.
• As compared to invertebrates model organisms, they
have more genes than other animals. As delicate organisms, special care must
be taken when handling them.
Unique
ability of Zebrafish
· Zebrafish has the
unique ability to repair the heart muscle.
ability of Zebrafish
· Zebrafish has the
unique ability to repair the heart muscle.
Zebrafish
age value
• Breed zebrafish has an
average life span of 3.5 years and can live up to 5.5 years.
• They show a gradual
aging process.
• Spine curvature has
been reported to be a common age-related phenotype.
age value
• Breed zebrafish has an
average life span of 3.5 years and can live up to 5.5 years.
• They show a gradual
aging process.
• Spine curvature has
been reported to be a common age-related phenotype.
Zebrafish
is teleost
is teleost
In recent decades, the tropical
teleost zebrafish (Danio rerio) has proven to be an excellent backbone system
for modeling mammalian molecular events that occur during embryonic
development, organ formation, physiology and adults, under normal or
pathological conditions.
teleost zebrafish (Danio rerio) has proven to be an excellent backbone system
for modeling mammalian molecular events that occur during embryonic
development, organ formation, physiology and adults, under normal or
pathological conditions.
Similarity
between the genetic material of zebrafish and humans
• Zebrafish has a genetic
structure similar to that of humans.
• 84 percent of the genes
known to be associated with human disease have a zebrafish equivalent.
• As a vertebrate, the
zebrafish has the same main organs and tissues as humans.
• Our muscles, blood,
kidneys and eyes share many characteristics with human systems.
between the genetic material of zebrafish and humans
• Zebrafish has a genetic
structure similar to that of humans.
• 84 percent of the genes
known to be associated with human disease have a zebrafish equivalent.
• As a vertebrate, the
zebrafish has the same main organs and tissues as humans.
• Our muscles, blood,
kidneys and eyes share many characteristics with human systems.
Taxonomy of Danio rerio ((F. Hamilton,
1822)
1822)
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Kingdom:
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Animalia
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Phylum:
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Chordata
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Class:
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Actinopterygii
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Order:
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Cypriniformes
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Family:
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Cyprinidae
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Genus:
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Danio
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Species:
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Danio rerio
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Advantages of zebrafish as a Model organism
Following are the advantages using zebrafish
as a model organism for any time animal research work
as a model organism for any time animal research work
External
fertilization:
fertilization:
As zebrafish eggs are fertilised
and grow outside the fish body. it can be used for studying early embryonic development and hence it is ideal
model organism to study developmental biology of animals including human
and grow outside the fish body. it can be used for studying early embryonic development and hence it is ideal
model organism to study developmental biology of animals including human
More
progeny:
progeny:
Zebrafish lays hundreds of eggs
which ultimately leads more offspring available for the research work as
compared to another model organism like rat
which ultimately leads more offspring available for the research work as
compared to another model organism like rat
Small
generation interval:
generation interval:
Generation interval or time for zebrafish is
three or four months, that mean you will get mature within 3 to 4 months
three or four months, that mean you will get mature within 3 to 4 months
Transparent
eggs or embryos:
eggs or embryos:
Zebrafish eggs or embryos are nearly crystal clear
or transparent which allows investigators to easily examine the development of
internal structures easily by any type of microscopy
or transparent which allows investigators to easily examine the development of
internal structures easily by any type of microscopy
Genome information:
Whole genome of
Zebrafish is available at different public database and it has a similar
genomics structure to humans. Zebrafish share 70 % of genes with human.
Zebrafish is available at different public database and it has a similar
genomics structure to humans. Zebrafish share 70 % of genes with human.
Maintenance of fish:
Zebrafish is inexpensive to
maintain than any other model organisms. You just need very small aquarium tank
for maintaining it.
maintain than any other model organisms. You just need very small aquarium tank
for maintaining it.
Vertebrate animal:
Zebrafish is a vertebrate
animal, it has the same main organs and tissues as other vertebrate animals
have e.g humans. Their muscle, blood, kidney and sensory organs system share
many features with human systems
animal, it has the same main organs and tissues as other vertebrate animals
have e.g humans. Their muscle, blood, kidney and sensory organs system share
many features with human systems
Morphological structures and growth rate:
Danio
rerio have pigmented body, on the
side of the body blue bands are present, which are reminiscent of a zebra’s
bands, and which range to the end of the caudal fin. Its growth rate is very
fast and can grow up to 4–5 cm (1.6–2.0 in) in length.
rerio have pigmented body, on the
side of the body blue bands are present, which are reminiscent of a zebra’s
bands, and which range to the end of the caudal fin. Its growth rate is very
fast and can grow up to 4–5 cm (1.6–2.0 in) in length.
During breeding time after introduce in breeding
tank within a few minutes the male fish of zebrafish chases the female in a
courtship procedural .After this, the female releases her eggs (spawning) to
the water tank, and the male immediately fertilizes them as per natural
phenomena. But In this work or experiment Kim Mitchell
et al., 2020 found that only 1 out of 10 couples with
mutated genes could spawn.
tank within a few minutes the male fish of zebrafish chases the female in a
courtship procedural .After this, the female releases her eggs (spawning) to
the water tank, and the male immediately fertilizes them as per natural
phenomena. But In this work or experiment Kim Mitchell
et al., 2020 found that only 1 out of 10 couples with
mutated genes could spawn.
Fish carrying mutations produce eggs and sperm,
but they do not breed with each other. When Kim
Mitchell et al., 2020 injected secretoneurin into the
body of genetically changed fish, fish can partially restore sexual functions.
but they do not breed with each other. When Kim
Mitchell et al., 2020 injected secretoneurin into the
body of genetically changed fish, fish can partially restore sexual functions.
Hence
this technique can be used to increase spawning in commercial cultured fish
species, or it can help human infertility treatments. Secretogranin-2 genes
also produce many other hormone-like peptides with unidentified functions. In
future, it will be exhilarating to explore this area of research work.
this technique can be used to increase spawning in commercial cultured fish
species, or it can help human infertility treatments. Secretogranin-2 genes
also produce many other hormone-like peptides with unidentified functions. In
future, it will be exhilarating to explore this area of research work.
Note: Credit of writing this article( Zebra Fish New Discovered Sex Hormone (Secretoneurin)
goes to Mehar Zafer and Mohd Ashraf.