in organisms with X and Y chromosomes, many more genes can be found on the X chromosome than on the Y chromosome. In mammals , how might this deviate from traits being expressed, according to mendel.

The fact that many more genes can be found on the X chromosome than on the Y chromosome means that genes that are limited to the X and Y chromosomes do not follow the Mendelian pattern of inheritance.

For recessive traits, it will ordinarily take 2 recessive alleles for a gene to be expressed according to Mendel (other things being equal). For organisms with X and Y chromosomes, only one recessive allele is required on either of the 2 chromosomes for the gene to be expressed.

For dominant traits, organisms can be true-breeding or heterozygous when the trait obeys Mendel's law. Organisms with X and Y chromosomes only require an allele for the trait to be expressed and the opportunity to be true-breeding or heterozygous does not arise.

In mammals with XY chromosomes, organisms with XX chromosomes are homogametic and those with XY chromosomes are heterogametic. The X chromosomes are homologous to one another but not to the Y chromosome.

Thus, recessive X-limited traits are usually more commonly expressed in organisms with XY chromosomes (because only one allele is needed) while any individual that inherits the Y chromosome automatically inherits the trait for the genes that the chromosome carries.