I. A. Moore investigated the inheritance of spotting...

I. A. Moore investigated the inheritance of spotting patterns in leopard frogs (I. A. Moore. 1943. Journal of Heredity $34: 3-7$ ). The pipiens phenotype had the normal spots that give leopard frogs their name. In contrast, the burnsi phenotype lacked spots on its back. Moore carried out the following crosses, producing the progeny indicated. (TABLE CANNOT COPY) a. On the basis of these results, what is the most likely mode of inheritance of the burnsi phenotype? b. Give the most likely genotypes of the parent in each cross (use $B$ for the burnsi allele and $B^{\prime}$ for pipiens allele) c. Use a chi-square test to evaluate the fit of the observed numbers of progeny to the number expected on the basis of your proposed genotypes.

I. A. Moore investigated the inheritance of spotting patterns in leopard frogs (I. A. Moore. 1943. Journal of Heredity $34: 3-7$ ). The pipiens phenotype had the normal spots that give leopard frogs their name. In contrast, the burnsi phenotype lacked spots on its back. Moore carried out the following crosses, producing the progeny indicated.
(TABLE CANNOT COPY)
a. On the basis of these results, what is the most likely mode of inheritance of the burnsi phenotype?
b. Give the most likely genotypes of the parent in each cross (use $B$ for the burnsi allele and $B^{\prime}$ for pipiens allele)
c. Use a chi-square test to evaluate the fit of the observed numbers of progeny to the number expected on the basis of your proposed genotypes.

Key Concepts

Dominant and Recessive Alleles

Dominant and recessive alleles describe the relationship between different versions of a gene. A dominant allele is one that expresses its phenotype even when only one copy is present, while a recessive allele requires two copies to produce its phenotype. This concept is crucial in predicting the outcomes of genetic crosses and understanding trait expression.

Genotype and Phenotype

The genotype is the genetic makeup of an organism, specifically the combination of alleles it carries for a particular trait, while the phenotype is the observable expression of this trait. The relationship between genotype and phenotype helps in understanding how genetic information translates into physical traits.

Mendelian Inheritance

Mendelian inheritance refers to the system of inheritance first described by Gregor Mendel, where traits are determined by discrete units (genes) that come in different versions (alleles). It involves patterns such as segregation and independent assortment, which explain how traits are passed from parents to offspring through predictable ratios.

Chi-Square Test

The chi-square test is a statistical method used to compare observed data with data expected under a specific hypothesis. In genetics, it is commonly used to assess whether the observed phenotypic ratios from a genetic cross differ significantly from the ratios predicted by Mendelian inheritance, thereby testing the validity of a hypothesized genetic model.

Transcript

00:01 In this problem, we're asked to consider the investigation of j.

00:04 A.

00:04 Moore into the inheritance of spotty patterns and leopard frogs.

00:09 The pipians phenotype has normal spots that give the leopard frogs their name.

00:15 In contrast, i think it's the bernsey phenotype, lacked spots on its back.

00:25 And moore carried out the following crosses, producing the progeny indicated.

00:30 For question a.

00:32 Based on results.

00:42 Burns, bernsie phenotype most likely inherited, or is the, is the bernsie phenotype most likely inherited as dominant or recessive? okay, i see that this has to be dominant.

01:33 Look at the bernsey, bernsie crossed, produced pipians, which must be recessive.

01:59 Okay, next question.

02:05 B.

02:10 I give most likely genotypes for each cross.

02:28 And we're going to use b for burns, bernz, and b.

02:38 Plus for, is it burz? burzzi? i can't tell what it is.

02:53 Maybe it's berzi.

02:57 Burzzi? okay, for pippian.

03:12 Pippians.

03:16 I'm going to go to the next page for this.

03:19 So we've got one, two, and three.

03:24 So here i'll have b and b plus, b and b plus.