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Can you read the numbers?

Explore the inheritance patterns of sex-linked disorders, such as color blindness, and understand how multiple alleles and incomplete dominance contribute to genetic traits. Learn about mutations and their impact on human genes. Participate in the Bean Passing Lab Activity to reinforce these concepts.

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Can you read the numbers?

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  1. Can you read the numbers?

  2. Sex-Linked Disorders • An allele inherited on a sex chromosome (sperm or egg) is called a sex-linked gene. • Color blindness is a sex-linked disorder in which people cannot distinguish between certain colors, particularly red and green. • This trait is a recessive allele on the X chromosome.

  3. Sex Determination • Each egg produced by a female normally contains one X chromosome. • Males produce sperm that normally have either an X or a Y chromosome. • When a sperm with an X chromosome fertilizes an egg, the offspring is a female, XX. • A male offspring, XY is the result of a Y-containing sperm fertilizing an egg.

  4. Multiple Alleles • Many traits are controlled by more than two alleles. • A trait that is controlled by more than two alleles is said to be controlled by multiple alleles. • Blood type in humans is an example of multiple alleles that produce only four phenotypes. • The alleles for blood types are called A, B, and O.

  5. Incomplete Dominance • When the offspring of two homozygous parents show an intermediate phenotype, this inheritance is called incomplete dominance.

  6. Human Genes and Mutations • Occasionally errors occur in the DNA when it is copied inside of a cell. • Such changes and errors are called mutations. • Not all mutations are harmful. They might be helpful or have no effect on an organism.

  7. Recessive Genetic Disorders • Many human genetic disorders, such as cystic fibrosis, are caused by recessive genes / a mutation of a gene. • Such genetic disorders occur when both parents have a recessive allele responsible for this disorder. Because the parents are heterozygous, they don’t show any symptoms. • If each parent passes the recessive allele to the child, the child inherits both recessive alleles and will have a recessive genetic disorder.

  8. Bean Passing Lab Activity • In pairs you will collect data on which finger combinations can partners use to pass a “bean” the most times in one minute. • We will then compare results with the entire class • Your LAB REPORT will be fully completed and handed in on Monday for home work.

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