Unit Notes

Child  Developmental  Psychology   X-Linked Inheritance à A harmful allele is carried on the X chromosome à Males more likely to be affected à Usually from the mother because male only has one X chromosome and depending on the disorder fertility and lifespan can be affected Chromosomal Abnormalities à Usually result from an error when a sperm or ovum is created (meiosis). When this occurs, either a chromosome pair does not separate properly or a part of a chromosome breaks off à Down syndrome is the most common chromosomal disorder §

In most cases, results from a failure of chromosome pair #21 to split in meiosis. End up with three chromosomes

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Intellectual disability, memory and speech problems, and slow motor development

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Distinct physical features: short/stocky, flat face, widely-spaced almond-shaped eyes

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Reduced life expectancy. More than half of those who live past age 40 show symptoms of Alzheimer’s disease

Sex Chromosomal Disorders

Male   Female   Male  

Female