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1
TAS
Angelfish Naming Convent=
ions
Part 1 – Genetic Notation
A Presentation for=
The
Angelfish Society
August 19, 2007=
3;
by
Tamar Stephens
![](3D"slide0001_image001.gif")
2
Introduction
•This presentation is the first part of a 2-part =
series.
•Part 1 will explain what genetic notation is, and =
how the TAS genetic notation for angelfish of the =
species Pt=
erophyllum
scalare is structured.
•Part 2 will explain how phenotype names are generated by the genetics calculator.
3
Vocabulary Refresher
•Chromosome
– Chromosomes occur in pairs, o=
ne
inherited from each
parent. Chromosomes contain =
the
genetic information for each individual.
•Allele – Alternate form of a gene. For example, black and gold are <=
/span><=
span
style=3D'font-size:63%'>alleles of each other.
•Phenotype – The appearance of an individual, such as =
smokey
or zebra.
<=
/span>
•Dominant
– An allele that expresses in t=
he
phenotype when present in a
single dose.
•Recessive – An allele that only expresses when in dou=
ble
dose.
•Co-dominant
– An allele that partially expr=
esses
in the presence of another
allele at the same locus. For
example, dark (D) and wild (+) are
co-dominant, resulting in a black lace, which blends the effects of <=
span
style=3D'font-size:63%'>both alleles to produce the black lace phenotype.<=
span
style=3D'mso-spacerun:yes'>
4
What is genetic notation?
•Genetic notation is =
a set =
of
symbols used to represent genes on chromosomes.
=
![](3D"slide0011_image002.jpg")
5
Types of Genetic Notation
•There are three prin=
cipal
styles of genetic notation in common use among scientists:
![](3D"slide0010_image004.gif")
![](3D"slide0010_image006.gif")
![](3D"slide0010_image008.gif")
Plant Notation
Animal Notation
Microbial Notation
6
TAS
uses a Modification of Animal Genetic
Notation
•<=
/span>Animal genetic notation is based on the concept of a “wild type” designated with the “+” symbol.
•
•<=
/span>“Wild type” means the most common phenotype.
•
•<=
/span>In TAS, “wild type” refers to <=
/span>the most common phenotype in wild angelfish, which we know as a wild silver, or just “wild.”
![](3D"slide0014_image009.jpg")
7
![](3D"slide0022_image010.gif")
Animal Genetic Notation Rules
Since gold is recessive to dark, =
animal
n=
otation
would use lower case “g” instead of upper case “G=
221;
for gold. A gold allele would be shown as Dg
4.
If there are more than two alleles, letter
superscripts are lower case if the second
allele is recessive to the initial dominant
allele, and upper case if it is dominant
to it.
Thus conventional animal notation=
would
s=
how
the wild allele as D+.
3.
The wild type allele is the same symbol
as the non-wild with a + superscript.
Since the dark allele is co-domin=
ant to
t=
he
wild type, we use upper case “D” instead of lower case “d”.
2.
If the non-wild allele is recessive, use a lower case letter to symbolize it. If non <=
span
style=3D'font-size:64%'>wild is dominant (or co-dominant), pick <=
span
style=3D'font-size:64%'>an upper case letter to symbolize it.
For example, we can pick
“D” to represent the dark or black phenotype.
1.
Pick a letter (or group of letters) that refers to the non-wild phenotype or the =
general characteristic.
8
![](3D"slide0012_image011.gif")
TAS Genetic Notation
• The notation used by The Ange=
lfish
Society is a modif=
ication
of animal notation. The symbols that would
normally be superscripts in animal genetic notation become the actual notation for the allele=
.
•
Gold =
allele
g
Dg
Gold =
marble
allele
Gm
DGm
Marble
allele
M
DM
Wild =
allele
+
D+
Dark
(black) allele
D
D
Allel=
es at
Dark Locus
TAS
Notation
Animal
Notation
9
![](3D"slide0021_image012.gif")
Animal
vs. TAS notation for some dark
locus phenotypes
M/M
DM/DM
Marble<=
/span>
D/+
D/D+
Black L=
ace
+/+
D+/D+
Wild si=
lver
TAS
Notation
Animal
Notation
Phenotyp=
e
![](3D"slide0021_image013.jpg")
Black L=
ace
Angelfish
10
Displaying notation for genes
•Chromosomes come in pairs. Genes therefore =
also come in pairs.
D/D .
like this: D/D
– S/S.
•Genetic notation shows the two paired genes separated by a forward slash like this:
•To show the genetic notation for more than one =
gene pair, each pair is separated by a hyphen
11
How does=
the
TAS Genetics Calcu=
lator
display the notation for a genotype?
12
TAS Gene=
tics
Calculator
•<=
/span>For any hypothetical cross, the calculator generat=
es:
–<=
/span>genotypes and the expected ratio of genotypes of t=
he
offspring, and
–<=
/span>phenotypes and expected ratio of phenotypes. (Phenotype naming will be the topic of another presentation)&=
#13;
•
•<=
/span>When more than one locus is involved in the phenot=
ype, the calculator shows the notation for the genotype=
in a specific order.
•
13
![](3D"slide0004_image014.gif")
The ge=
netics
calculator displays the alleles
at each locus in this order:
Strea=
ked
(St)
8
Albin=
o (a)
7
Pearl=
y (p)
6
Half-=
black
(h)
5
Veil =
(V)
4
Smoke=
y (Sm)
3
Zebra=
/Stripeless
Locus (Z,S)
2
Dark =
Locus
(D, M, Gm, g)
1
14
Let’s look at an example
15
![](3D"slide0008_image015.gif")
How
would the calculator show the genotype
for a black ghost veil tail?
Streaked
Locus (St) =
;
à
(none)
8
Albino=
Locus
(a) =
; &n=
bsp;
à
(none)
7
Pearly=
Locus
(p) =
; &n=
bsp;
à
(none)
6
Half-b=
lack
Locus (h) =
;
à (no=
ne)
5
Veil Locus (V) =
; &n=
bsp;
à =
;
V/+
4
Smokey=
Locus
(Sm) =
;
à (no=
ne)
3
Zebra/Stripeless
Locus (Z,S) à
S/+
2
Dark
Locus (D, M, Gm, g) =
;
à D/+
1
When
you list the alleles in
order, the genotype is:
D/+
– S/+ - V/+
![](3D"slide0008_image016.jpg")
16
![](3D"slide0009_image017.gif")
You
can also show the genotype to include
loci with all wild alleles
Streak=
ed
Locus (St) =
;
à =
;
+/+
8
Albino=
Locus
(a) =
; &n=
bsp;
à =
;
+/+
7
Pearly=
Locus
(p) =
; &n=
bsp;
à =
;
+/+
6
Half-b=
lack
Locus (h) =
;
à =
;
+/+
5
Veil Locus (V) =
; &n=
bsp;
à =
;
V/+
4
Smokey=
Locus
(Sm) =
;
à =
;
+/+
3
Zebra/=
Stripeless
Locus (Z,S) à=
;
S/+
2
Dark L=
ocus
(D, Gm, g) =
;
à
D/+
1
You
could display loci with all wild alleles, and show
the genotype as:
D/g – S/+ - +/+ - V/+ - +/+ - +/+ - +/+ - +/+
However,
this gives a cluttered look.
The
genetics calculator simply omits the loci =
that
have only wild alleles when it displays a
genotype.
17
Let’s try another example
•
How would you show the genotype
of a half-black veil t=
ail ghost?
![](3D"slide0019_image018.jpg")
18
![](3D"slide0017_image019.gif")
Half-bla=
ck
veil tail ghost
Streaked
Locus (St) =
;
à
(none)
8
Albino=
Locus
(a) =
; &n=
bsp;
à
(none)
7
Pearly=
Locus
(p) =
; &n=
bsp;
à =
;
p/p
6
Half-black
Locus (h) =
;
à h/h
5
Veil Locus (V) =
; &n=
bsp;
à
V/+
4
Smokey=
Locus
(Sm) =
;
à (no=
ne)
3
Zebra/Stripeless
Locus (Z,S) =
à
S/+
2
Dark L=
ocus
(D, Gm, g) =
;
à
(none)
1
Simply
list the alleles in the order in which they appear
in the chart.
The
first non-wild alleles are on the stripeless
locus (S/+), followed by the veil locus
(V/+) and then the half-black locus (h/h).
=
String
these together in order to get:
S/+-V/+-h/h
19
Does the order really matter?
•<=
/span>Probably not.&nbs=
p;
You would probably call
this fish a half-black veil tail.
•
•<=
/span>The genetics calculator would show the genotype as V/+-h/h.
•
•Most of us would probably list the <=
span
style=3D'position:absolute;top:52.5%;left:9.73%;width:42.88%;height:4.0%'>=
half-black alleles first – h/h-V/+ - =
because that is the dominant =
appearance of the angelfish.
•
•<=
/span>And anyone familiar with TAS <=
span
style=3D'font-size:56%'>angelfish notation will recognize the genotype and interpret it =
correctly in either order.
![](3D"slide0023_image020.jpg")
V/+-h/h=
or
h/h-V/+?