Question

Решите задачу, у хлопчыка 2-я гомазиготная група крыви а у яго сястры 3-я гетэразиготная вызначце генатыпы их бацькоу напишыце скрыжаванне.

Answer 1

Думаю решать надо так:

Answer 2

Problem Analysis

The problem states that a boy has a 2nd homozygous blood group, and his sister has a 3rd heterozygous blood group. We need to determine the genotypes of their parents and write the crossing.

Solution

To solve this problem, we need to understand the inheritance patterns of blood groups. The ABO blood group system is determined by the presence or absence of certain antigens on the surface of red blood cells. There are four main blood types: A, B, AB, and O.

The ABO blood group is determined by three alleles: A, B, and O. The A and B alleles are codominant, while the O allele is recessive. The possible genotypes and phenotypes for the ABO blood group system are as follows:

- Genotype AA: Blood type A - Genotype AO: Blood type A - Genotype BB: Blood type B - Genotype BO: Blood type B - Genotype AB: Blood type AB - Genotype OO: Blood type O

Based on the information given in the problem, we can deduce the following:

1. The boy has a 2nd homozygous blood group. This means he has a homozygous genotype for blood type A, which can be either AA or AO. 2. The girl has a 3rd heterozygous blood group. This means she has a heterozygous genotype for blood type B, which can be either BB or BO.

Now, let's determine the possible genotypes of their parents and write the crossing.

Possible Genotypes of Parents

Since the boy has a homozygous blood group (either AA or AO) and the girl has a heterozygous blood group (either BB or BO), we can deduce the following possibilities for their parents' genotypes:

1. Father: AA, Mother: BB - In this case, the father has a homozygous genotype for blood type A (AA), and the mother has a homozygous genotype for blood type B (BB). The boy would inherit one A allele from the father and one B allele from the mother, resulting in the genotype AB (blood type AB). The girl would inherit one A allele from the father and one B allele from the mother, resulting in the genotype AB (blood type AB).

2. Father: AA, Mother: BO - In this case, the father has a homozygous genotype for blood type A (AA), and the mother has a heterozygous genotype for blood type B (BO). The boy would inherit one A allele from the father and one B allele from the mother, resulting in the genotype AB (blood type AB). The girl would have a 50% chance of inheriting the A allele from the father and the B allele from the mother, resulting in the genotype AB (blood type AB), and a 50% chance of inheriting the O allele from the mother, resulting in the genotype AO (blood type A).

3. Father: AO, Mother: BB - In this case, the father has a heterozygous genotype for blood type A (AO), and the mother has a homozygous genotype for blood type B (BB). The boy would have a 50% chance of inheriting the A allele from the father and the B allele from the mother, resulting in the genotype AB (blood type AB), and a 50% chance of inheriting the O allele from the father, resulting in the genotype AO (blood type A). The girl would inherit one A allele from the father and one B allele from the mother, resulting in the genotype AB (blood type AB).

4. Father: AO, Mother: BO - In this case, both the father and the mother have heterozygous genotypes for blood types A (AO) and B (BO), respectively. The boy would have a 25% chance of inheriting the A allele from the father and the B allele from the mother, resulting in the genotype AB (blood type AB), a 25% chance of inheriting the A allele from the father and the O allele from the mother, resulting in the genotype AO (blood type A), a 25% chance of inheriting the O allele from the father and the B allele from the mother, resulting in the genotype BO (blood type B), and a 25% chance of inheriting the O allele from both parents, resulting in the genotype OO (blood type O). The girl would have the same possibilities.

Crossing

Based on the possible genotypes of the parents, we can write the crossing as follows:

1. Father: AA, Mother: BB - Crossing: AA x BB - Possible offspring: AB (blood type AB)

2. Father: AA, Mother: BO - Crossing: AA x BO - Possible offspring: AB (blood type AB), AO (blood type A)

3. Father: AO, Mother: BB - Crossing: AO x BB - Possible offspring: AB (blood type AB)

4. Father: AO, Mother: BO - Crossing: AO x BO - Possible offspring: AB (blood type AB), AO (blood type A), BO (blood type B), OO (blood type O)

Please note that the actual genotypes and blood types of the parents can only be determined through genetic testing. The possibilities mentioned above are based on the given information and the known inheritance patterns of the ABO blood group system.

I hope this helps! Let me know if you have any further questions.