Due: Pre Lab Discussion
Monster Genetics Lab
Heredity is the passing on of traits, or characteristics, from parent to offspring. The units of heredity are
called genes. Different versions of the same gene are called alleles. Genes are found on the chromosomes
in a cell. The comdinations of genes for each trait occur by chance.
When one allele in a pair is stronger than the other allele, the trait of the weaker allele is masked, or
hidden. The stronger allele is the dominant allele, and the allele that is masked is the recessive allele.
Dominant alleles are written as capital letters and recessive alleles are written as lowercase letters. If both
alleles are different, the trait is said to be heterozygous, or hybrid. Sometimes alleles are neither dominant
nor recessive. The result of such a situation is a blending of traits.
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The genetic makeup of an individual is known as its genotype. The observable physical characteristics of an
individual that are the result of the genotype are known as its phenotype.
In humans, the sex of an individual is determined by the particular combination of the two sex
chromosomes. Individuals that have two X chromosomes (XX) are females, whereas those with an X and a Y
chromosome (XY) are males,
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In this investigation, you will work with a partner to observe how the results of different gene combinations
produce certain traits.
Problem: How are traits inherited?
Materials:
Pencil
Lab Sheet