Fish Cell Biology/Genetics Fish Cell Biology/Genetics BasicsBasics

Dr. Craig KasperDr. Craig Kasper

HCC BrandonHCC Brandon

Fig. 01-05Fig. 01-05

Fig. 01-07Fig. 01-07

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Fig. 01-11Fig. 01-11

Zebra Fish Larval DevelopmentZebra Fish Larval Development

• We thank We thank Leon Browder & & Laurie Iten (Ed.) (Ed.) Dynamic DevelopmentDynamic Development for their for their gracious use of material seen in slides 11-gracious use of material seen in slides 11-17.17.

• We also thank We also thank Haffter Haffter et al.et al., 1996 and , 1996 and The Company of Biologists for their The Company of Biologists for their contributions.contributions.

Previous Slide Info…Previous Slide Info…

Figure 2. Drawings of zebrafish embryos at 24 Figure 2. Drawings of zebrafish embryos at 24 hours (A), 48 hours (B,D) and 5 days (C,E) of hours (A), 48 hours (B,D) and 5 days (C,E) of development. For clarity, the pigmentation development. For clarity, the pigmentation pattern is omitted from B and C. It is shown pattern is omitted from B and C. It is shown

in D and E. Most of the structures that can be in D and E. Most of the structures that can be seen in a living embryo with a compound seen in a living embryo with a compound

microscope are labeled. (From Haffter microscope are labeled. (From Haffter et al.et al., , 1996. Reproduced with permission from The 1996. Reproduced with permission from The

Company of Biologists.)Company of Biologists.)

Gregor Mendel: Quick ReviewGregor Mendel: Quick Review

• You might look at possible outcomes for your You might look at possible outcomes for your fish some day. It would be nice to know what to fish some day. It would be nice to know what to expect, or how you “got what you got…”expect, or how you “got what you got…”

• Punnett Squares and knowledge of basic Punnett Squares and knowledge of basic genetics will help you determine what traits you genetics will help you determine what traits you select for maybe in your breeding. (At least until select for maybe in your breeding. (At least until you spawn several groups.) More on Punnett you spawn several groups.) More on Punnett Squares shortly…Squares shortly…

IntroductionIntroduction

• As always we have several new terms.As always we have several new terms.• GenotypeGenotype: genes of the individual. Your : genes of the individual. Your

genetic makeup, if you will.genetic makeup, if you will.• PhenotypePhenotype: What you look like, or more : What you look like, or more

precisely, what physical manifestations are precisely, what physical manifestations are observed.observed.

• AlleleAllele: Alternate forms of a gene which are : Alternate forms of a gene which are located in the same position on a pair of located in the same position on a pair of chromosomes.chromosomes.

Fig. 02-01Fig. 02-01• Three paths: Three paths: Two results??Two results??

• Not really!Not really!

• Again, new terms…Again, new terms…

• Dominant allele Dominant allele (capital letter)(capital letter)

• Recessive AlleleRecessive Allele (lower case letter)(lower case letter)

• Alleles on autosomesAlleles on autosomes

• Basic Mendelian Genetics Basic Mendelian Genetics and the Punnett Squareand the Punnett Square

• If we “cross multiply,” it If we “cross multiply,” it becomes evident that not becomes evident that not all genotypes result in the all genotypes result in the same phenotype. same phenotype.

• The example at the left is a The example at the left is a single-trait cross.single-trait cross.

• Notice the expected Notice the expected phenotypic ratiophenotypic ratio (3:1). (3:1). This will become important This will become important later.later.

• What happens if we What happens if we mix it up a bit??mix it up a bit??

• Same method, differentSame method, different results.results.

• Now the phenotypicNow the phenotypic ratio is 50:50 (Better oddsratio is 50:50 (Better odds than you’d get in Vegas!)than you’d get in Vegas!)

• Okay, Emeril, let’s…Okay, Emeril, let’s… ““Kick it up a notch!!”Kick it up a notch!!”

• Dihybrid crossesDihybrid crosses (and beyond) are (and beyond) are handled similarly.handled similarly.

• You must be carefulYou must be careful to transfer all yourto transfer all your alleles though!!alleles though!!

• Once this is done, Once this is done, figuring out what figuring out what you have can beyou have can be challenging.challenging.