Question

Solve the following Genetics Problems

1. In mice the autosomal genotype yy is for gray fur, YY is for brown fur and Yy is for yellow fur. What is the ratio of offspring from the cross between a brown mouse and a yellow mouse?
2. ABO blood groups, an autosomal trait, in Humans are genetically determined. A woman with type O blood has a son with type O.

What are the possible genotype(s) of the son, his mother and possible father?

                Mother:

Father:

                Son:

3. A couple is concerned that their son may inherit the bleeding disorder hemophilia. This condition is caused by a recessive allele on the X-chromosome. The wife is a carrier for this condition, while the husband has hemophilia.

   What are the genotypes of this couple?

   What is the probability of the couple having a son who is a hemophiliac?

Answer 1

1). Answer

a). The gray mouse is homozygous (because it's a clean line). If the gray coat was dominant, we would see all the gray mice. Since we get both yellow and gray mice, the yellow color should be predominant over the gray one.
The gene symbol is gray = y and yellow=Y.

From the above analysis, the color of the gray mouse should be yy. The mouse was homozygous we would not see any gray mouse from the cross, which is why genotypes should be heterozygous or Yy. should give an estimate of 3 yellow: 1 gray. The result, however, was a count of 2 yellow to one gray mouse.

So we can make a Punnett square:

		Female Gamet	Female Gamet
		Y	y
Male Gametes	Y	YY yellow	Yy yellow
Male Gametes	y	Yy yellow	yy gray

As we can see, we should take 3: 1 percent yellow to gray mice. Can one race be childless. Since we already know the colors of gray and yy mice. Most of the testcross and yellow mice provide a comparison of 1: 1. This comparison is similar to that seen with heterozygous individuals. Consequently, all yellow mice on the cross of two yellow mice are Yy. Somehow the YY genotype is a killer. The 2: 1 ratio is an estimate of the type of lethal gene.

b). The human blood type is determined by the major supplies. The allele is one of several types of genetic information found in our DNA at a particular location on a particular chromosome. There are three different types of human blood cells, known as IA, IB, and i.

We can denote it, A (for ), B (for ), and O (for i).

Each of us has two ABO blood groups because we all receive one type of blood from our biological mother and the other from our biological father. The expression of many disorders in our DNA is called the genotype. Since there are three different types of links, there are six possible genetic variants in the ABO genetic locus. The different genotypes include AA, AO, BB, BO, AB, and OO.

A blood test is used to determine if A A / or B characteristics are present in the blood sample. It is not possible to determine the exact genotype by testing blood type A or type B. If someone has type 'A' blood, they should have one copy of A allele, but they may have two copies. Their genotype is either AA or AO. Similarly, someone with type B blood may have a genotype or BB or BO.

A blood test for any type of AB or type O is most effective. Someone with type AB blood must have both A and B levels. The color must be AB. Someone with type O blood has neither A nor Bule. The genotype ought to be OO.

Apiece biological parent gives their child one of the two alleles of their ABO. A mother with blood type O can only transmit O allele to her son or daughter. A father with blood type AB could pass either A or B alleles to his son or daughter. This pair could have children of type A or blood type, O from mother and A from father, or blood type B, O from mother and B from father.

Rh mutants are also inherited from our parents but are born on their own without ABO blood type. There are two distinct levels of Rh factor known as Rh + and Rh-. Someone who is "Rh positive" or "Rh-negative" has an Rh + allele but may have two. Their species can be Rh + / Rh + or Rh + / Rh-. Someone who Rh- has an Rh- / Rh- type.

Type of Father blood	Father genotype	Mother blood	Mother genotype	Son blood type
A	AA, AO	A	AA, AO	A, O
AB	AB	A	AA, AO	A, AB, B
B	BB, BO	A	AA, AO	A, AB, B, O
O	OO	A	AA, AO	A, O

Type of Father blood	Father genotype	Mother blood	Mother genotype	Son blood type
A	AA, AO	AB	AB	A, AB, B
AB	AB	AB	AB	A, AB, B
B	BB, BO	AB	AB	A, AB, B
O	OO	AB	AB	A, B

Type of Father blood	Father genotype	Mother blood	Mother genotype	Son blood type
A	AA, AO	B	BB, BO	A, AB, B, O
AB	AB	B	BB, BO	A, AB, B
B	BB, BO	B	BB, BO	B, O
O	OO	B	BB, BO	B, O

Type of Father blood	Father genotype	Mother blood	Mother genotype	Son blood type
A	AA, AO	O	OO	A, O
AB	AB	O	OO	A, B
B	BB, BO	O	OO	B, O
O	OO	O	OO	O

2). Answer

a). Hemophilia is usually an inherited blood condition in which blood is not normal. This can cause immediate bleeding and bleeding after injury or surgery. Blood contains a lot of protein called clotting substances that can help keep blood from losing blood. The degree of hemophilia a person has is determined by the amount of a substance in the blood. The lower the amount of the substance, the more likely it is that bleeding occurs which can cause severe health problems.

In some cases, hemophilia can occur in adulthood. Most cases involve elderly or middle age or young women who have recently given birth or who have a low pregnancy rate. This is usually determined by proper treatment.

Hemophilia is affected by a mutation or alteration of one of the genes, which provides instructions for the production of clotting factor proteins required for thrombus formation. This change or mutation may interfere with the normal functioning of the clotting protein or may be absent. These genes are located on the X chromosome. Men have one X and one Y chromosome (XY) and women have two X chromosomes (XX). Men inherit the X chromosome from their mothers and the Y chromosome from their parents. Females inherit one X chromosome from a father or mother.

A daughter is inherited by an X chromosome from her mother and an X chromosome from her father. The conjecture that the X chromosome from its mother has a gene for normal blood clotting. Suppose that an X chromosome from its father contains a hemophilia gene. A daughter does not develop hemophilia since a special blood type from her mother is the best. It does not allow instructions from hemophilia to be sent.

Daughter is called carrier hemophilia. She has a gene on one of her X chromos and can pass it on to her offspring. Of these, it does not mean that only women are responsible for hemophilia. It is the mother who undergoes hemophilia. However, a man's sperm is the deciding factor in whether the child will be male or female. It's not the "fault" of one parent since both parents contribute to this. We all have strange genes. We don't know many of them. It is only by chance that hemophilia is given to produce a child with hemophilia.

When a baby inherits a Y chromosome from the father it becomes a boy baby. Since the Y chromosome does not carry the hemophilia gene, a male born with hemophilia and a non-carrier female may not have hemophilia.When a baby gets an X chromosome from a father it becomes a girl. X chromosomes from men with hemophilia will have a type of hemophilia. But the girl also receives an X chromosome from her mother. The normal type of blood that comes out of a woman is strong. She will be, the bearer of hemophilia since she has a type of hemophilia on one of her X chromosomes.

b). As a mother, it is a carrier that can share one X chromosome. There is a 50% chance she will give her mutated chromosome to her daughters and she has a 50 percent chance of passing on the gene to his sons, who will develop the disease. The male sperm has an X or Y chromosome. Eggs embedded from the X chromosomes turn into female eggs and the embryos from the Y chromosomes become male. This means that none of his sons will suffer from hemophilia because he inherits his X chromosome, but his daughters may have a 50-50 possibility of being a conveyor of the disease.

In a rare case where a mother and father have X chromos involved, there is a 50% chance that their son will be born with hemophilia. There is a 50% chance that their daughters will be pregnant and 50% more likely to have this condition.