Sex cell development in females

These smaller masses have a higher ratio of surface area to volume when compared to large masses, making it easier for them to be digested.

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In the cells of humans and many other organisms the sex chromosomes consist of a pair of chromosomes called the X and Y chromosomes.

Stomach, Gallbladder and Pancreas

Males and females are independently capable of producing offspring. They have two types of cells in all their organs, each with one of the two X chromosomes genetically active and the other essentially silent.

Sex Chromosomes

It is not entirely clear how the inactivating gene, XIST, causes this change in the X chromosome, but the result is the same as in the temporary or permanent inactivation of genes that are not needed in the cells of particular tissues. Sexual reproduction, on the other hand, provides possibilities for variation among offspring and thus assists evolution by allowing new pairs of genes to combine in offspring. Page explains how successive inversions and deletions of the Y chromosome during mammalian evolution have reduced it to its present form—small and sparsely populated with genes. Menu Genomics home Health professionals Policy makers Patients and public Ethical, legal and social implications Research Craniofacial anomalies. The Y chromosome acts as a dominant inducer of male phenotype and individuals having four X chromosomes and one Y chromosome 49XXXXY are phenotypically male.