Home | About Us | Contact Us


Koi Forum - Koi-Bito Magazine straight from Japan
Page 1 of 7 123 ... LastLast
Results 1 to 10 of 61

Thread: Genetic Research in Koi

  1. #1
    Nisai
    Join Date
    Jan 2012
    Posts
    91

    Genetic Research in Koi

    Recently we performed some study on koi genetics at Kentucky State University. I attached PDF file with article, which was written based on results of this study. I understand that this article is pretty specialized but it should be interesting for forum users taking into account questions and concerns on fish cloning and DNA technology methods.

    I am ready to provide some explanations and answer questions.

    BorG
    Attached Thumbnails Attached Thumbnails Genetic Research in Koi-alsaqufi-et-al.-aquaculture-research.pdf  

  2. #2
    Daihonmei MikeM's Avatar
    Join Date
    Dec 2003
    Location
    Orlando, Florida
    Posts
    11,128
    Well, it is rather technical, but I'm sure JR will appreciate a published study that includes citation to Dr. Kuroki.

  3. #3
    Daihonmei
    Join Date
    Sep 2006
    Posts
    7,642
    Quote Originally Posted by MikeM View Post
    Well, it is rather technical, but I'm sure JR will appreciate a published study that includes citation to Dr. Kuroki.
    \

    Now THAT'S just mean! LOLs
    JR, North American District Chairman of ZNA
    ( in the line of three) of the two districts outside of Japan that are deemed enlightened enough to
    have a seat on the board!

    "sticks and stones my Southern chapter president, sticks and stones!"

  4. #4
    Jumbo RobF's Avatar
    Join Date
    Jan 2009
    Location
    Orlando, FL
    Posts
    617
    Who says hitting your head on the wall won’t attract the attention of the girl next door?

    I do have some questions, for a start:

    1. You produced lines of homozygous koi how similar is color and pattern among the sisters?
    2. What do you know about kohaku color and pattern that you didn’t know in 2003?
    3. As you say homozygous common carp are not new, how new, different,or cost effective is the use of microsatellites to verify homozygosity?

  5. #5
    Daihonmei
    Join Date
    Sep 2006
    Posts
    7,642
    Quote Originally Posted by BorG View Post
    Recently we performed some study on koi genetics at Kentucky State University. I attached PDF file with article, which was written based on results of this study. I understand that this article is pretty specialized but it should be interesting for forum users taking into account questions and concerns on fish cloning and DNA technology methods.

    I am ready to provide some explanations and answer questions.

    BorG

    Great paper Boris. Keep up the good work! Question, how much of your perspective on this subject ( not the technical advacement but the punnett square perspective) was formed by the work done by Roth ( bard) in Israel in the 1980s and 90s? JR

  6. #6
    Nisai
    Join Date
    Jan 2012
    Posts
    91

    Some explanations

    In this study we used DNA microsatellite markers to evaluate the level of homozygosity offish produced by two types of gynogenesis. This method is very special and applied only in fish and amphibian but not to other vertebrate animals (as mammals).

    I would like to provide some general information on induced gynogenesis and specifics of cloning in fish. In mammals clones are obtained by nuclear transplantation. Clones in mammals have been produced from early 1990s but from the beginning nuclei for transpalantation were taken from early embryonic cells. In the case of cloning of sheep Dolly (in 1996) there was breakthrough since nucleus for this transplantation was taken from specialized (mammary) tissue taken was adult animal. Mammary tissue was first cultured and later nucleus from one cell was transplanted to egg, from which original nucleus was removed. So, Dolly was genetically identical to sheep from which mammary tissue was originally taken. Asyou know now clones are obtained in other mammals as cats and dogs. In all these cases it is possible to produce copy of adult organism. But this method is pretty difficult and does not allow to produce many cloned organisms (before obtaining Dolly scientists performed more than 200 unsuccessful transplantations).

    In fish clones are obtained by means of induced gynogenesis. What are the basics of this method? Eggs are inseminated with genetically inactivated sperm (usually by irradiation), that is chromosomes of spermatozoa are destroyed and do not participate in embryo development (but irradiated spermatozoa are still motile and are capable to inseminate eggs). In order to produce viable gynogeneticfish the chromosome set from egg should be doubled (as compensation for inactivation of spermatozoa chromosomes). It can be done by suppression of either 2ndmeiotic division in eggs, which occurs in koi in about 5-6 min afterinsemination (early shock, meiotic gynogenesis), or of first mitotic division in haploid embryos in about 45-50 min after insemination (lates hock, mitotic gynogenesis).

    Gynogenesis results in increase in homozygosity and can be considered as inbreeding, which is crossing of relatives. The extreme form of inbreeding is self-fertilization which can be observed in plants or hermaphroditic animals. In the case of self-fertilization coefficient of inbreeding (which measures the level of homozygosity) is 0.5. In animals reproducing by normal sexual mode the highest possible level of inbreeding can be achieved by crossing of brother x sister. In this case coefficient ofinbreeding is 0.25. In case of meiotic gynogenesis the coefficient of inbreeding is about 0.5, close to one which is observed in case of self-fertilization. In case of mitotic gynogenesis coefficient of inbreeding is 1.0 (maximum value); it means that 100% genes in fish obtained by mitotic gynogenesis are homozygous. This is because two homologous chromosomes in these fish are products of simple mitotic reduplication in haploid embryos. This uniqueness of mitotic gynogenetic fish is used for production of clones (or geneticallyidentical fish). Clones can be produced by two methods. First method: from females obtained by means of mitotic gynogenesis the 2nd consecutive gynogenetic generation (meiotic or mitotic) is obtained. Progenies produced from individual females will be clones. Second method: Some fish from progeny obtained by mitotic gynogenesis are sex-reversed by hormonal treatment, that is males of mitotic gynogenetic origin are obtained. Crossing of females and sex-reversed males of the mitotic gynogenetic origin will be clones. For the first time clones in fish have been obtained in model species zebrafish in 1981. From that time clones have been obtained in several fish species includingcommon carp.

    Let’s compare production of clones in fish using mitotic gynogenesis with method used in mammals (nuclear transplantation). In fish it is possible to produce very numerous clones (thousands of fish) but it is impossible to clone given adult fish. In other words it is impossible to clone koi champions. I think that theoretically by using induced gynogenesis it would be possible to obtain clones in koi but these fish will have relatively low quality.

    In conclusion I would like to note that studies on nuclear transplantations (similar to ones in mammals) have been performed in fish also. In 1984 Chinese scientists reported successful embryo development after transplantation of nucleus from kidney tissue to egg with removed original nucleus. But I doubt that somebody will try copy high quality koi by this very difficult method.

  7. #7
    Nisai
    Join Date
    Jan 2012
    Posts
    91
    Quote Originally Posted by RobF View Post
    Who says hitting your head on the wall won’t attract the attention of the girl next door?

    I do have some questions, for a start:

    1. You produced lines of homozygous koi how similar is color and pattern among the sisters?
    2. What do you know about kohaku color and pattern that you didn’t know in 2003?
    3. As you say homozygous common carp are not new, how new, different,or cost effective is the use of microsatellites to verify homozygosity?
    Here are answers to your questions:

    1.You produced lines of homozygous koi how similar is color and pattern among the sisters?

    Actually fish of first generation of induced gynogenesis (both meiotic and mitotic) are not lines; these progenies are pretty variable (with regard to color too). If we obtain second consecutive gynogenetic generation from females of mitotic gynogenetic origin we produce clones.

    3. As you say homozygous common carp are not new, how new, different,or cost effective is the use of microsatellites to verify homozygosity?

    Clones in common carp using mitotic gynogenesis have been obtained before, but not in koi. Why there is need to check complete homozygosity in late-shocked, presumably mitotic gynogenetic progenies? Since in fish some viable gynogenetic diploids can appear without any shocks by spontaneous supression of the 2nd meiotic division in eggs. That is we apply late shock with intention to produce mitotic gynogens but resulted progeny will include meiotic gynogens too. Usually meiotic gynogenetic fish are more viable since they are not completely homozygous and therefore their proportion can increase with fish age. We will not produce clones if from meiotic gynogenetic females the second consective gynogenetic generation will be produced. DNA microsatellite markers are very popular currently in fish population genetics. As we noted in article they were used earlier to prove mitotic gynogenesis in some other fish; we applied this method in koi.


    2.What do you know about kohaku color and pattern that you didn’t know in 2003?

    I knew and know that this trait is very complex and combines features of both qualitative and quantitative traits. My suggestion is that background body color (white or red) is controlled by some major genes but coverage with red in white-red fish is very variable and under control of many genes with relatively low conribution each. This is a hypothesis, for its confirmation more experimental data are needed.

  8. #8
    Nisai
    Join Date
    Jan 2012
    Posts
    91
    Quote Originally Posted by JasPR View Post
    Great paper Boris. Keep up the good work! Question, how much of your perspective on this subject ( not the technical advacement but the punnett square perspective) was formed by the work done by Roth ( bard) in Israel in the 1980s and 90s? JR
    Thanks Jim. I think that Punnett square method can work in koi for some simple traits such as, for example, inheritance of black pigment (wild pigmentation of common carp or presence of bekko black spots) or "design" - trait typical for metallic koi (ornament on head and stripe along dorsal fin). But for more complex traits as Kohaku this method cannot be applied.

    Boris G

  9. #9
    Daihonmei MikeM's Avatar
    Join Date
    Dec 2003
    Location
    Orlando, Florida
    Posts
    11,128
    Quote Originally Posted by BorG View Post
    In this study we used DNA microsatellite markers to evaluate the level of homozygosity offish produced by two types of gynogenesis. This method is very special and applied only in fish and amphibian but not to other vertebrate animals (as mammals).

    I would like to provide some general information on induced gynogenesis and specifics of cloning in fish. In mammals clones are obtained by nuclear transplantation. Clones in mammals have been produced from early 1990s but from the beginning nuclei for transpalantation were taken from early embryonic cells. In the case of cloning of sheep Dolly (in 1996) there was breakthrough since nucleus for this transplantation was taken from specialized (mammary) tissue taken was adult animal. Mammary tissue was first cultured and later nucleus from one cell was transplanted to egg, from which original nucleus was removed. So, Dolly was genetically identical to sheep from which mammary tissue was originally taken. Asyou know now clones are obtained in other mammals as cats and dogs. In all these cases it is possible to produce copy of adult organism. But this method is pretty difficult and does not allow to produce many cloned organisms (before obtaining Dolly scientists performed more than 200 unsuccessful transplantations).

    In fish clones are obtained by means of induced gynogenesis. What are the basics of this method? Eggs are inseminated with genetically inactivated sperm (usually by irradiation), that is chromosomes of spermatozoa are destroyed and do not participate in embryo development (but irradiated spermatozoa are still motile and are capable to inseminate eggs). In order to produce viable gynogeneticfish the chromosome set from egg should be doubled (as compensation for inactivation of spermatozoa chromosomes). It can be done by suppression of either 2ndmeiotic division in eggs, which occurs in koi in about 5-6 min afterinsemination (early shock, meiotic gynogenesis), or of first mitotic division in haploid embryos in about 45-50 min after insemination (lates hock, mitotic gynogenesis).

    Gynogenesis results in increase in homozygosity and can be considered as inbreeding, which is crossing of relatives. The extreme form of inbreeding is self-fertilization which can be observed in plants or hermaphroditic animals. In the case of self-fertilization coefficient of inbreeding (which measures the level of homozygosity) is 0.5. In animals reproducing by normal sexual mode the highest possible level of inbreeding can be achieved by crossing of brother x sister. In this case coefficient ofinbreeding is 0.25. In case of meiotic gynogenesis the coefficient of inbreeding is about 0.5, close to one which is observed in case of self-fertilization. In case of mitotic gynogenesis coefficient of inbreeding is 1.0 (maximum value); it means that 100% genes in fish obtained by mitotic gynogenesis are homozygous. This is because two homologous chromosomes in these fish are products of simple mitotic reduplication in haploid embryos. This uniqueness of mitotic gynogenetic fish is used for production of clones (or geneticallyidentical fish). Clones can be produced by two methods. First method: from females obtained by means of mitotic gynogenesis the 2nd consecutive gynogenetic generation (meiotic or mitotic) is obtained. Progenies produced from individual females will be clones. Second method: Some fish from progeny obtained by mitotic gynogenesis are sex-reversed by hormonal treatment, that is males of mitotic gynogenetic origin are obtained. Crossing of females and sex-reversed males of the mitotic gynogenetic origin will be clones. For the first time clones in fish have been obtained in model species zebrafish in 1981. From that time clones have been obtained in several fish species includingcommon carp.

    Let’s compare production of clones in fish using mitotic gynogenesis with method used in mammals (nuclear transplantation). In fish it is possible to produce very numerous clones (thousands of fish) but it is impossible to clone given adult fish. In other words it is impossible to clone koi champions. I think that theoretically by using induced gynogenesis it would be possible to obtain clones in koi but these fish will have relatively low quality.

    In conclusion I would like to note that studies on nuclear transplantations (similar to ones in mammals) have been performed in fish also. In 1984 Chinese scientists reported successful embryo development after transplantation of nucleus from kidney tissue to egg with removed original nucleus. But I doubt that somebody will try copy high quality koi by this very difficult method.
    I am thinking about how far in the future it is when we get a post from a 'newbie' who wants advice on what she is doing wrong in obtaining sex-reversed males. ...A hundred years ago much we now discuss as being elementary was mind-bending.

  10. #10
    Jumbo RobF's Avatar
    Join Date
    Jan 2009
    Location
    Orlando, FL
    Posts
    617
    How do color and pattern track in subsequent generations (F2,F3. Etc) of homozygous koi clones?

    Could a heterozygote clone of a female fish be produced by using the egg prior to the ejection of the second polar body (or some other intervention)?

Page 1 of 7 123 ... LastLast

Similar Threads

  1. Genetic Engineering?
    By RayJordan in forum Main Forum
    Replies: 12
    Last Post: 08-09-2012, 10:14 AM
  2. Genetic Predisposition to Shimis in Kohaku
    By schildkoi in forum Main Forum
    Replies: 259
    Last Post: 11-09-2010, 07:30 AM
  3. Evolutionary and genetic nomenclature . . .
    By KoiCop in forum Main Forum
    Replies: 12
    Last Post: 12-12-2006, 08:58 PM
  4. Koi surgery ...research project
    By Ian_&_Terri in forum Main Forum
    Replies: 11
    Last Post: 11-14-2006, 05:14 PM
  5. Koi Health Research
    By mrbradleybradley in forum Main Forum
    Replies: 3
    Last Post: 06-21-2005, 04:03 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Articles - Sitemap - FAQs and Rules

KB Footer Graphic
Straight from Japan... For the serious hobbyist!
All content and images copyright of: Koi-bito.com