In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. mating two of the f1 fish fails to produce females with the trait. explain the inheritance pattern of the trait.
Sex linked trait
Sex linkage is the phenomenon in which the expression of genes depends on the gender of the organisms because genes for specific traits are located on the sex chromosomes of organisms. If repeated crosses of the fish indicate the pattern that long tail fins appear only in males and not in females, it means the trait is linked to the male sex.
What are sex chromosomes:
They are usually a pair of chromosomes present in higher organisms like humans and other mammals that combine during fertilization of male and female gametes and determine the sex of offspring. In humans they are X and Y chromosomes and when there is an XX offspring, she will e female and when there will be XY offspring , he will be male.
Significance:Now there are some genes that are present only on sex chromosomes of the organisms like genes for beard are present in human Y chromosome of men, However,genes found on the X chromosome can be found in either males or females.Sex linked genetic disorders are very common in human males because males receive only one copy of X chromosome while females receive two copies. So only one copy of defective gene is enough for the expression of disease in males while in women two copies are needed if the trait is recessive.For example: There is a disease called hemophilia in which the blood is unable to clot even after minor injuries and can be life threatening.Hemophilia is an X linked recessive disorder and is an example of sex linked traits controlled by sex linked genes.
Hope it helps!
In this cross the trait of long tail fins is associated with the “Y” chromosome of the male.
Thus the alleles of the male are represented by XY” where X chromosome has no trait of long tails find
And the allels of the female are represented by XX, as they do not have long tail fins.
When these two are crossed , the following punnet square is produced
XX X X Y”
X X X X Y”
The XX is the female while the XY” is the male offspring.
The inheritance pattern is of sex linked
Genes that are carried by either sex chromosome are said to be sex linked. Men normally have an X and a Y combination of sex chromosomes, while women have two X's. Since only men inherit Y chromosomes, they are the only ones to inherit Y linked traits.
this would be a math