Unit 8 Flashcards
What is a gene
Information for a trait passed from a parent to an offspring, requires two alleles to function in most cases
What is an allele
Alternate forms of a gene ( one can be P and the other p)
What is a Phenotype
The observable physical and physiological trait resulting from gene expression
What is a genotype
The genetic constitution/set of allele (BB or Bb)
What are homozygous genotypes
2 of the same allele
What is a heterozygous genotype
Having two different allele
What is a hemizygous genotype
Having only one allele because of sex-linked traits
What is the difference between autosomes and sex chromosomes
Autosomes are the same, can be written as Bb, BB or bb
Sex chromosome contain X and Y, can be written like this
XBXB, XBXb, XbXb
Name the 8 inheritance patterns
-simple dominance
-intermediate/incomplete pattern
-co-dominance
-epistasis
-polygenic
-pleiotropic
-multiple allele: hierarchical
-multiple allele: circular
What did mendel contribute to genetics
He figured out:
-how traits are handed down from parent to offspring during gamete formation
-how alleles interact and are expressed in the offspring-simple dominance
What are Mendels 3 principles
-principle of segregation
-principle of dominance
-principle of independent assortment
What is the principle of segregation
Genes of one parent behaves as pairs and seperate so that each gamete contains only one of the two
What is Principle of dominance
When alternate forms of a gene are together and one hides the expression of the other=dominant/recessive
What is principle of independent assortment
When 2 different traits/genes are located on different chromosomes, the alleles assort independently into gametes during meiosis
Why are garden pea plants a good genetic tool?
-pea hybrids could be produced and many pea varieties
-one plant produced many offspring
-pea plants are easy to grow and reach maturity after 60-70 days
-peas self fertilize, but can be cross fertilized, permitting gene control
What does the monohybrid experiment determine?
The principle of segregation and the principle of dominance
Decribe the monohybrid experiment
-homozygous with opposite alleles are bred
-a heterozygous is produced and then self-fertilized, where the offsprings have a 3:1 ratio
What is a reciprocal cross
When you breed the same genotypes but with different sexes
In autosomal genes, it should give the same thing, but should change for sex-linked
What is the evidence gained from the monohybrid cross
-even if the first generation only had purple flowers, the white flowers reappear in the second generation, thus whit was hidden but not lost
-since white is present in the second generation, it means that both alleles were present in the first generation, thus did seperate during meiosis
What is simple dominance
When one allele of a gene completely hides the expression of the second allele
How to find the genotype of dominant phenotype
Cross it with a homozygous recessive
How do you make a prediction in genetics?
You do a punett square
What is mendels model of inheritance
-each trait is controlled by one gene
-each gene only has two alleles
-there is a clear dom-res relationship between the two
