Is it more indicated for a geneticist desiring to map the X chromosome of the mother of a given family (the researcher does not have access to her DNA, only access to the genetic material of the offspring) to analyze the chromosomes of her daughters or of her sons?
To analyse the X DNA of a mother (assuming no access to her own material) it is more indicated to study the genetic material of her sons since all X chromosomes of males come from the mother while the daughters have X chromosomes from the mother and from the father. Through the researching the material of the sons it is ensured that the studied X chromosome is from the mother.