Genetics and Chromosomal Concepts

The video introduces autosomal linkage, explaining the concept using chromosomes and genes. It covers genetic crosses, meiosis, and independent assortment, illustrating these with a Drosophila fruit fly example. The video concludes with a summary and offers additional resources for A-level biology students.

How many pairs of chromosomes are present in a human cell?

• 25 pairs

• 24 pairs

• 23 pairs

• 22 pairs

What is the term for genes located on the same chromosome?

• Recessive genes

• Independent genes

• Linked genes

• Autosomal genes

What process results in the independent separation of genes during meiosis?

• Gene linkage

• Gene mutation

• Independent assortment

• Gene duplication

In a pea plant, what are the possible gametes if the genes for seed color and shape are on different chromosomes?

• Two types

• Three types

• Four types

• Five types

What happens to linked genes during crossing over if they are closely located on the same chromosome?

• They are always separated

• They are always inherited together

• They mutate

• They are less likely to be separated

In Drosophila, what is the dominant allele for body color?

• Red

• Black

• Grey

• White

What is the phenotype ratio of offspring in a dihybrid cross with autosomal linkage in Drosophila?

• 2:2

• 1:1

• 3:1

• 4:0

Which allele combination results in vestigial wings in Drosophila?

• Nn

• nn

• NN

• nN

What is the result of a dihybrid cross of two heterozygotes with autosomal linkage?

• Two have dominant traits, two have recessive traits

• All offspring have dominant traits

• All offspring have recessive traits

• Three have dominant traits, one has recessive traits

What is the purpose of using a Punnett square in genetic crosses?

• To predict the phenotype and genotype of offspring

• To identify mutations

• To determine the number of chromosomes

• To measure DNA length