Answer and Explanation: The allele for wrinkled seed shape in garden peas is considered recessive because the trait associated with the allele is not expressed in heterozygotes. Heterozygotes are individuals that have two different alleles for a particular gene locus.
What are recessive alleles?
Definition. A type of allele that when present on its own will not affect the individual. Two copies of the allele need to be present for the phenotype to be expressed.
What is the genotype for a wrinkled seed?
The shape of the seeds are controlled by two alleles Round (R) and Wrinkled (r). Round shape is the dominant one and wrinkled shape is the recessive trait. Now for wrinkled phenotype to be shown, the genotype has to be recessive homozygous. Therefore, the genotype of wrinkled phenotype is rr.
What is the genetic basis of wrinkled phenotype of wrinkled peas seeds?
So, the wrinkled phenotype of pea seed is given by double recessive ‘rr’ genotype.
Why can’t phenotypes of haploid organisms be dominant or recessive?
Answer and Explanation: The alleles present in haploid organisms like bacteria do not have dominant or recessive traits because dominance and recessiveness occur when gene alleles interact. The haploid organism has only one copy of the gene with only one allele. Hence no dominant or recessive trait occurs.
How can you tell if an allele is dominant or recessive?
Dominant alleles are seen as an uppercase of a letter; for example, B. Recessive alleles are seen as a lower case of a letter; b. In order for a person to show the dominant trait, one of the person’s parents must have the dominant trait (which is an uppercase letter).
How do you know if its dominant or recessive?
If the trait is dominant, one of the parents must have the trait. Dominant traits will not skip a generation. If the trait is recessive, neither parent is required to have the trait since they can be heterozygous.
Are wrinkled seeds dominant or recessive?
recessive trait
In Mendel’s experiment, “wrinkled seed” is a recessive trait.
Are wrinkled peas dominant or recessive?
Because the allele that produces wrinkled peas is recessive, the offspring of this cross will all have wrinkled peas. Mendel then explains the concept of dominant and recessive alleles by saying, “By performing my experiments with peas, I learned a lot about genetics and how traits are passed on.
Are wrinkled seeds recessive?
In pea plant, round seed is a dominant trait while wrinkled seed is a recessive trait.
What causes the wrinkled seed phenotype?
Increased sucrose concentration in the developing embryos of this mutant line causes increased uptake of water and thereby increases the cell size and fresh weight. During seed maturation in these mutant seeds a greater loss of water occurs. As a result, the wrinkled seed phenotype develops.
What’s the name of the gene that has a mutation or is absent in the wrinkled pea plant that results in a wrinkled phenotype?
The wrinkled-seed mutant (rr) of pea (Pisum sativum L.) arose through mutation of the gene encoding starch-branching enzyme isoform I (SBE1) by insertion of a transposon-like element into the coding sequence.
What is the phenotype of round wrinkled seed shape?
The phenotypic ratio from the cross is 1 : 1. For 99 round and 300 wrinkled seeds, the ratio is approximately 1:3. For 301 round and 100 wrinkled seeds, the ratio is approximately 3:1.
Why can’t phenotypes of haploid organisms be dominant or recessive quizlet?
The alleles found in haploid organisms cannot be dominant or recessive because: only one allele is present, alleles in haploid organisms are always dominant.
Why Most mutations in a diploid organism are recessive?
Why are most mutations in a diploid organism recessive? In most cases, the amount of product from one gene of each pair is sufficient for production of a normal phenotype.
How many alleles does a haploid have?
one allele
A haploid cell carries only one allele of each gene.
What makes something recessive?
Individuals inherit two versions of each gene, known as alleles, from each parent. In the case of a recessive trait, the alleles of the trait-causing gene are the same, and both (recessive) alleles must be present to express the trait. A recessive allele does not produce a trait at all when only one copy is present.
Why are some alleles dominant and some recessive?
The two alleles for a gene don’t need to be the same. The instructions you get from your mom can be a little different from the instructions you get from your dad. And these different instructions — or alleles — will end up making slightly different proteins. This is where dominant and recessive come from.
What is meant by dominant and recessive genes give one example of each?
The dominant gene is represented by a capital letter and the corresponding recessive gene is represented by the corresponding small letter. For example, in pea plants, the dominant gene for tallness is T and the recessive gene for dwarfness is t.
Which pair of alleles represent a recessive trait?
Recessive alleles are denoted by a lowercase letter (a versus A). Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait.
Why is a dominant allele called dominant?
Allele refers to variants of the same gene that occur on the same chromosome. An allele is said to be dominant as they override or mask the effect of other variants available for the same gene.