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Explain the following terms: (i) Pedigree herd (ii) Recessive allele (iii) Natural service (iv) Independent assortment - Leaving Cert Agricultural Science - Question 7 - 2019
Question 7
Explain the following terms: (i) Pedigree herd (ii) Recessive allele (iii) Natural service (iv) Independent assortment. (b) In the squash plant, the allele for ... show full transcript
Worked Solution & Example Answer:Explain the following terms: (i) Pedigree herd (ii) Recessive allele (iii) Natural service (iv) Independent assortment - Leaving Cert Agricultural Science - Question 7 - 2019
Step 1
Explain the term: Pedigree herd
Answer
A pedigree herd consists of animals that are all descended from a purebred lineage. This ensures that the genetic traits of the herd are well-documented and can be traced back to a specific ancestor, providing a clear understanding of inheritance patterns.
Step 2
Explain the term: Recessive allele
Answer
A recessive allele is an allele that is not expressed in the phenotype when paired with a dominant allele. It only manifests its traits when two copies of the recessive allele are present, meaning that an individual must inherit the recessive allele from both parents for its associated traits to be observable.
Step 3
Step 4
Explain the term: Independent assortment
Answer
Independent assortment is the principle that when two or more pairs of alleles segregate during gamete formation, the alleles of each pair assort independently of one another. This means that the inheritance of one trait will not affect the inheritance of another trait.
Step 5
Step 6
Outline four reasons why fruit flies (Drosophila) are used for genetics experiments.
Answer
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Large number of offspring: Drosophila produce a significant number of offspring in a short time, which allows for extensive genetic studies in a limited time frame.
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Short reproductive time: Their rapid life cycle makes it possible to observe multiple generations in a brief period.
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Easily identified traits: They have easily observable traits that can be used to study inheritance patterns, such as eye color and wing shape.
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Simple chromosome structure: Drosophila have a relatively simple and well-mapped genome, making it easier to study genetic mutations and their effects.
Step 7
Comment on the lambing percentage
Answer
The lambing percentage is calculated as follows:
ext{Lambing Percentage} = rac{ ext{Number of Lambs Born}}{ ext{Number of Ewes}} imes 100
oindent In this case:
ext{Lambing Percentage} = rac{180}{100} imes 100 = 180\.
This indicates a very high lambing percentage, suggesting productive ewes. The observed ratio of 92 rams to 88 ewes hints at a near-equal distribution of male and female lambs, which is beneficial for herd management.