A testcross can
be used to determine the organism’s genotype. In a testcross, the individual with the unknown genotype is crossed with a homozygous recessive individual (Figure below). Consider the following example: Suppose you have a purple and white flower and purple color (P) is dominant to white (p).
Can you be sure of the genotypes of the affected siblings of individual 3 explain?
3. Can you be sure of the genotypes of the affected siblings of individual #3? Explain.
No
, as long as have one copy of the dominant allele, they will have the trait.
Can you determine the genotypes of any individuals in the pedigree if so which ones?
You may not always be able to determine the genotype of an individual based on a pedigree. Sometimes an individual can either be homozygous dominant or heterozygous for a trait. Often, we can use
the relationships between an individual and their parents, siblings, and offspring
to determine genotypes.
Can you determine the genotype of an individual if you know the phenotype?
Today, scientists use the word “phenotype” to refer to what Mendel termed “external resemblance” and the word “genotype” to refer to an organism’s “internal nature.” Thus, to restate Mendel’s musing in modern terms,
we cannot infer an organism’s genotype by simply observing its phenotype
.
What is the phenotype of an individual?
A phenotype is
an individual’s observable traits, such as height, eye color, and blood type
. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.
How do you explain a pedigree chart?
A pedigree chart displays a family tree, and
shows the members of the family who are affected by a genetic trait
. This chart shows four generations of a family with four individuals who are affected by a form of colorblindness. Circles represent females and squares represent males.
What is the genotype of individual?
A genotype is
an individual’s collection of genes
. The term also can refer to the two alleles inherited for a particular gene. … The expression of the genotype contributes to the individual’s observable traits, called the phenotype.
How many generations are shown in this pedigree?
| A B | How many generations are shown on this pedigree?, 3 generations are shown. | Which individual is a female affected by the trait of interest?, I-2 is the affected female. | Which individual is a male affected by the trail of interest?, III-2 is the affected male. |
|---|
What information can be deduced from a pedigree?
By analyzing a pedigree, we can determine genotypes, identify phenotypes, and predict how a trait will be passed on in the future. The information from a pedigree makes it possible to determine
how certain alleles are inherited
: whether they are dominant, recessive, autosomal, or sex-linked.
What are the 3 types of genotypes?
There are three types of genotypes:
homozygous dominant, homozygous recessive, and hetrozygous
.
What are examples of phenotype?
Examples of phenotypes include
height, wing length, and hair color
. Phenotypes also include observable characteristics that can be measured in the laboratory, such as levels of hormones or blood cells.
Which allele is always written first?
When expressing dominant and recessive alleles,
the dominant allele
is always written as a capitalized letter, and the recessive allele as the same letter, but lower case.
What is difference between genotype and phenotype?
The sum of an organism’s observable characteristics is their phenotype. A key difference between phenotype and genotype is that,
whilst genotype is inherited from an organism’s parents, the phenotype is not
. Whilst a phenotype is influenced the genotype, genotype does not equal phenotype.
What are two examples of phenotypes?
- Eye color.
- Hair color.
- Height.
- Sound of your voice.
- Certain types of disease.
- Size of a bird’s beak.
- Length of a fox’s tail.
- Color of the stripes on a cat.
How many phenotypes can be expressed?
There are three common alleles in the ABO system. These alleles segregate and assort into six genotypes, as shown in Table 1. As Table 1 indicates, only
four phenotypes
result from the six possible ABO genotypes.
What is the purpose of a pedigree chart?
A pedigree is a genetic representation of a family tree that
diagrams the inheritance of a trait or disease though several generations
. The pedigree shows the relationships between family members and indicates which individuals express or silently carry the trait in question.
