Dihybrid Cross Concepts and Phenotypes

This video tutorial covers dihybrid inheritance, focusing on Mendel's experiments with pea plants. It explains the formation of gametes, Mendel's law of independent assortment, and the concept of unlinked genes. The video details the outcomes of dihybrid crosses, including the typical 9:3:3:1 ratio, and discusses the use of statistical tests to analyze genetic data.

What is the main focus of a dihybrid cross?

• Inheritance of multiple alleles

• Inheritance of linked genes

• Inheritance of two different genes

• Inheritance of a single gene

What does Mendel's Law of Independent Assortment state?

• Dominant alleles are always expressed

• Alleles in a pair can combine randomly with alleles in another pair

• Alleles in a pair are always inherited together

• Genes on the same chromosome are inherited independently

In Mendel's experiments, which seed shape is dominant?

• Wrinkled

• Round

• Green

• Yellow

What genotype represents pure breeding round yellow seeds?

• RRYy

• rryy

• RrYy

• RRYY

What is the expected phenotypic ratio in a dihybrid cross?

• 1:1

• 3:1

• 2:1

• 9:3:3:1

How many types of gametes can be formed by a heterozygous parent in a dihybrid cross?

• One

• Four

• Two

• Three

What is the phenotype of F1 offspring in Mendel's dihybrid cross?

• Wrinkled green seeds

• Round green seeds

• Wrinkled yellow seeds

• Round yellow seeds

What might cause the observed phenotypic ratio to differ from the expected 9:3:3:1?

• Dominant alleles

• Independent assortment

• Linked genes

• Large number of offspring

What statistical test is mentioned for comparing observed and expected ratios?

• ANOVA

• Chi-square test

• Z-test

• T-test

What does 'unlinked genes' refer to in the context of Mendel's experiments?

• Genes on different chromosomes

• Genes that do not assort independently

• Genes on the same chromosome

• Genes that are always inherited together