A XXX karyotype is an abnormality that is found in one in every 1000 female human births. It is caused by a missing or extra X chromosome, resulting in an imbalance of sex chromosomes in the body.
In order to understand how this could have occurred during meiosis, we must first understand how meiosis works. During meiosis I, a diploid cell divides into two haploid cells. The haploid cells are then recombined during meiosis II to form the gametes. During this process, the mother’s chromosomes cross over with the father’s, resulting in a variety of possible combinations.
In the case of the XXX karyotype, it is likely that the mother or father had a defect in meiosis I, resulting in an extra or missing X chromosome. This could have occurred if the mother was heterozygous for a trait on the X chromosome and the father was recessive for this gene. In this case, the daughter would be homozygous recessive for this trait, as the XX combination would only have one recessive gene.
Overall, the XXX karyotype is caused by a defect in meiosis I, resulting in an extra or missing X chromosome. In the case of a mother who was heterozygous for a trait on the X chromosome and the father was recessive for this gene, the daughter would be homozygous recessive for this trait. This is due to the fact that the XX combination would only have one recessive gene.
Learn more about Meiosis I at :https://brainly.com/question/29383386
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Assertion Reason Question:
Assertion (A) - The rhythmic beating of various chambers of the heart maintain circulation of blood.
Reason (R) - Pulse rate per minute indicates the rate of heart beat.
(i) Both A and R are true and R is the correct explanation of A.
(ii) Both A and R are true but R is not the correct explanation of A.
(iii) A is true but R is false.
(iv) A is false but R is true.
Answer: B
Explanation: Both A and R are true but R is not the correct explanation of A.
