鬥魚的基因 遺傳專們術語
Terminology of genetics
By: Joep van Esch
Submitted: 6/29/2004
對於鬥魚遺傳育種方面 首先就是要先了解遺傳學相關的術語囉
One thing that is really important with genetics is to understand the terminology used. I will try here to clarify some of the basics which are indispensable in betta genetics [1,2,3].
DNA: Deoxyribonucleic acid, the heritable material of an organism.
(相信這個大家都知道吧 遺傳生命的起源 去氧核糖核酸 )
Gene: The units of inheritance that transmit information from parents to offspring.
(由去氧核糖核酸 所組成的稱為 基因 她可以傳遞由父母親所帶有的遺傳訊及表現性狀給她的子代)
Chromosomes: A long threadlike association of genes in the nucleus of all eukaryotic cells which are visible during meiosis and mitosis. A chromosome consists out of DNA and proteins. An organism always has 2n chromosomes, which means that all chromosomes are paired.
(染色體是一個由基因組成的股螺旋結構存在於真核細胞裡得細胞核只有當細胞進行 有絲分裂減數分裂的時候(如經卵生成 及胚胎發育)才可以在顯微鏡下看見) 而染色體上的基因 可以轉錄及轉譯(合成)陶多多的蛋白質 而這些蛋白質可以決定鬥魚 性狀(如顏色 或是外表等等) 此外有性生殖的真核生物裡面 由於需來自父母親得基因 所以囉 染色體通常是成對的 (除性染色體外 XY chromosome)
Genotype: This is the genetic makeup of an organism: the genes
( 基因型 是指一隻鬥魚所具有的基因組成)
Phenotype: The physical and physiological traits of an organism.
These are influenced by genetic makeup (genes) and surrounding.
(表現型 是指一隻鬥魚所具有的外在及內在特點 而表現型主要會受到基因型的後天環境的影響)
Allele: Another word for gene. Each chromosome has a copy of this allel, thus a gene-pair.
(對偶基因 是指染素體上都具有一對基因 所以稱為對偶基因)
Homozygous: This term indicates that an organism has two identical alleles at a single place on a chromosome. This results in an organism that breeds true for only one trait.
同型結合 染色體上 相同位置上所來自父母的基因 是相同的 因此只會有一種表現
Heterozygous: This term indicates that an organism has two different copies of a gene on each chromosome.
異型結合 染熱體上相同位置上有兩種不同的基因
Dominant gene: In a heterozygote, this allele (gene) is fully expressed in the phenotype. In genetic schemes, these genes are always depicted with a capital letter.
顯性基因 是指當異型結合時 表現較強的那個基因 所以子代得表現都會受顯性基因的影響
Recessive gene: In a heterozygote, this allele (gene) is completely masked in the phenotype. In genetic schemes, these genes are always depicted with a lower case letter.
隱性基因 與顯性基因相反的 這是較弱的表現基因 所以性狀會被跼�
除非父母親都有隱性基因 才會表現這種性狀
Intermediar gene: This is when in a heterozygote, an allele (gene) is not fully masked in the phenotype. You can already see some of the characteristics of the gene. A good example is the dt-gene (see tail type definitions & genetics).
中間型基因 (等顯性基因)
子代得性狀表現同時受到來自父母親基因的影響 (這個主要影響鬥魚尾旗的基因表線)
I think I now covered the basics….. now an example to visualize this using the allel for hair color in humans:
講了這麼多專業的術語 接下來 用國中生物的基礎來舉個例子
Brown hair is a dominant trait. How is it possible that two parents with brown hair get a blond daughter of son?
假如 深褐色是 顯性基因 那麼父母親都是深褐色的時候 假如她們的子代是金色的 那麼父母親的基因為何呢 ??
The allel for “brown hair” is dominant and depicted with “B”.
The allel for “blond hair” is recessive and depicted with “b”.
B :代表顯性 褐色基因
b: 代表隱性 金色基因
The answer lies here: Remember that all alleles come in pairs and that the parents have to be heterozygous for the allel for haircolor. This means that both parents have to posses the recessive trait for blond hair (“b”) besides the dominant trait for brown hair (“B”), thus “Bb”. The best thing to visualize this is by the use of a Punnet-square:
所以囉 由四方格得方式 你可以推測 父母親得染素體上應該都是異型結合的(同時帶有顯性及隱性) 所以她們雖然都是褐色的 但是子代會出現金色的喔
Summary: The offspring of two parents carrying the heterozygous “Bb” genotype can result in the following offspring: 25% homozygous for brown hair (“BB”), 50% heterozygous for brown hair (“Bb”) and 25% homozygous for blond hair (“bb”)
所以他們的子代 的基因型 會有 25%BB 50% Bb 及 25% bb
但是表現型 則會有75%是深褐色的 25% 是金色的喔
Then some basic rules about genetic crosses.
When two unrelated parents are crossed their hybrid offspring are called the F1 generation (for the first filial generation).
When the F1 offspring is interbred their offspring will be called the F2 generation (for the second filial generation).
When the F2 offspring is interbred their offspring will be called the F3 generation (for the third filial generation). And so on........
遺傳育種的基本原理
當兩個來源不同的父母親 所得的後代 我們稱為 F1 子代
當F1 互相交尾 所的的子代稱為 F2 子代 依此類堆.....
This interbreeding of offspring can be done up to F8, but one has to check the offspring very carefully each generation on abnormalities. So it is advisable to use an out-cross (unrelated partner, fresh blood) once in a while.
When one of these offspring (doesn';t matter of which generation) is crossed with an unrelated partner, their offspring is again F1
在作純化育種上 最好只能做到 第八代 (F8) 但是此時要非常小心的檢查你的第八代魚 因為有可能釵h導致突變隱性的基因 會呈現出來 有時會造成魚之外觀不正常
所以最好在第八代的時候 在重新 找一之外血系的種魚囉
這樣又可以重新算起囉
.文獻出處:
Literature:
1. Campbell, N.A., “Biology”, Fourth edition, The Benjamin/Cummings Publishing Company, Inc., ISBN 0-8053-1940-9
2. Zakwoordenboek der Geneeskunde, 25ste geheel herziene druk, Elsevier/Koninklijke PBNA, ISBN 90-6228-255-5
3. Betta Bunnies genetic page,
http://www.geocities.com/Petsburgh/Farm/5592/genetics.html 
