X-linked recessive traits inheritance pattern

X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be always expressed in males (who are necessarily homozygous for the gene mutation because they have one X and one Y chromosome) and in females who are homozygous for the gene mutation, see zygosity. Females with one copy of the mutated gene are carriers. X-linked inheritance means that the gene causing the trait or the disorder is located on the X chromosome. Females have two X chromosomes while males have one X and one Y chromosome. Carrier females who have only one copy of the mutation do not usually express the phenotype, although differences in X-chromosome inactivation (known as skewed X-inactivation) can lead to varying degrees of clinical expression in carrier females, since some cells will express one X allele and some will express the other. The current estimate of sequenced X-linked genes is 499, and the total, including vaguely defined traits, is 983. #genetics #xlinkedGeneticTrait #inheritance #PunnetSquare #biology #XlinkedTraits #genotype #phenotype #KhanAcademy #XChromosome #NikolaysGeneticsLessons #geneticDisease #geneticDisorder #DNA #RNA #geneticsDisorders #homozygous #hemizygous #chromosomes #XChromosomeInheritance #dominantTrait #geneticDesease #XlinkedRecessive #AutosomalRecessive #GeneticsExamQuestionsSolutions #SexlinkedDominant #skewedXinactivation #Xlinked #sexlinkedRecessive