Lecture 16 - Alleles And Inheritance Flashcards
What are Mendel’s Laws of Inheritance?
- Principle of Segregation
- Principle of Independent Assortment
What is the Principle of Segregation?
Alleles separate such that only one randomly chosen allele ends up in a gamete
What is the Principle of Independent Assortment?
-Separation of chromosomes (thus genes) is Independent
(Separation of a pair of genes is independent of the separation of other pairs of genes)
(The other allele a gamete receives (for a given gene) does not affect the allele received for other genes)
What did Mendel believe about the Expression of Traits?
- chromosomes on a gamete are randomly selected from maternal and paternal chromosomes
What is complete dominance?
Trait expressed the same way for homozygous and heterozygous genotypes
- with a different expression for recessive traits
What is Co-Dominance/ No-Dominance?
- neither allele masks the other
- both expressed with heterozygous genotypes
- characteristic intermediate to both homozygous genotypes
What is an example of co/no - dominance
Roan coat color in shorthorn cattle
What is in-complete or particularly dominance?
An allele is expressed in 2 dependent manner
- offspring is intermediate between 2 alleles
What are some examples of in-complete or partial dominance?
- red + white = pink
- palomino
What is epistasis?
Effect of one gene depends on the alleles present at one or more loci
- modifier genes
What are sex-linked inheritance?
Traits inherited through X chromosome
What is a sex limited trait?
Trait is limited to a sex
Milk production
Sex-influenced trait
Trait is influenced by gender
- an allele that is dominant in one sex is recessive in the other sex
(Polled vs horned for male vs female)
What is the strategy of animal breeding? The goal?
Identification and selection of superior animals
To produce animals that excel for desired traits while minimizing occurrence of undesirable traits
What are the 2 tools for genetic change?
Selection - obtain a desirable phenotype through choosing animals for mating
Mating - pairing of males and females
