Genetics and Inheritance Patterns

The video tutorial covers Mendelian genetics, focusing on dominant and recessive traits in pea plants and guinea pigs. It explains genetic crosses between homozygous and heterozygous plants, detailing the resulting genotypic and phenotypic ratios. The tutorial also explores working backwards from offspring traits to determine parental genotypes, using examples of insect wing traits.

What is the expected phenotype of the offspring when two homozygous tall pea plants are crossed?

• 75% tall, 25% dwarf

• 50% tall, 50% dwarf

• 100% dwarf

• 100% tall

When crossing two heterozygous tall pea plants, what is the probability of obtaining a dwarf offspring?

• 75%

• 50%

• 25%

• 0%

In a cross between a heterozygous tall plant and a dwarf homozygous plant, what is the expected phenotypic ratio?

• 4 tall : 0 dwarf

• 1 tall : 1 dwarf

• 3 tall : 1 dwarf

• 2 tall : 2 dwarf

What is the genotype of a guinea pig with long hair if long hair is recessive?

• Homozygous recessive

• None of the above

• Homozygous dominant

• Heterozygous

What is the expected phenotypic ratio when crossing two heterozygous short-haired guinea pigs?

• 4 short : 0 long

• 1 short : 3 long

• 2 short : 2 long

• 3 short : 1 long

In Mendel's first experiment with pure breeding guinea pigs, what was the phenotype of the offspring?

• All short-haired

• 50% short-haired, 50% long-haired

• 75% short-haired, 25% long-haired

• All long-haired

If 50% of the offspring have short wings and short wings are recessive, what can be inferred about the parents?

• Both parents are heterozygous

• Both parents are homozygous dominant

• One parent is homozygous dominant, the other is homozygous recessive

• One parent is homozygous recessive, the other is heterozygous

What is the genotypic ratio when two heterozygous insects are crossed, given that long wings are dominant?

• 1:2:1

• 3:1

• 2:2

• 4:0

What is the probability of obtaining a homozygous dominant offspring when two heterozygous parents are crossed?

• 50%

• 0%

• 75%

• 25%

In a cross where 25% of the offspring are homozygous recessive, what is the most likely genotype of the parents?

• Both homozygous dominant

• Both homozygous recessive

• Both heterozygous

• One homozygous dominant, one heterozygous