Chromosomal Basis of Inheritance Flashcards
Define: Transmission Genetics
How gene are inherited by following the products of gene expression in the form of characteristics.
Define: Gene
The dsDNA sequence that codes for RNA/Protein. Includes non-coding control elements (Promoters).
- Considered the “units” of inheritance
What sis the central dogma?
DNA(gene)–> mRNA –> Protein
Define: Chromosomes
Long dsDNA molecule containing different genes
- 22 pairs of autosomes (2 copies of every gene), 1 pair sex chromosomes
-Imaged in a karyotype
Define: Haploid
Containing 1 copy of every gene
- Prokaryotic cells
Explain: Meiosis
Two cell divisions in germ cells to produce gametes
-prophase, metaphase, anaphase, and telophase
-Genetic diversity!
-Haploid
Explain: Mitosis
One cell divisions in somatic cells to produce two identical daughter cells during growth and repair
- Diploid
Describe how meiosis ensures genetic diversity
- Crossing over: An exchange of DNA between homologous chromosomes in prophase 1.
- Independent assortment: Arrangement of sister chromatids at the equatorial plane in metaphase is random
Define: Genotype
Genetic composition (alleles/genes) of an organism
Define: Phenotype
Detectable manifestation of a gene (Visible/physical)
Define: Wild type
Natural or standard lab form of a genotype or phenotype for a particular organism
Define: Allele
Different versions of the same gene (Diploid= 2 alleles)
Define: Mutation
A difference in the nucleotide sequence difference from the wild type.
Define: Homozygous
Diploid containing identical alleles for a gene
Define: Heterozygous
Diploid containing different alleles for a gene
Describe: Dominant
Phenotype expressed from one of the alleles in a heterozygote.
Describe: Recessive
Phenotype that is not expressed from one allele in a heterozygote. Phenotype is only observed in homozygous recessive progeny
Describe: Monohybrid Cross
A cross between 2 organisms that are both heterozygous for a sing trait being followed
- Could also be a dihybrid or trihybrid cross
Describe how to identify a dominant and recessive allele
1) Homo. dominant (+/+) crossed with homo. recessive (-/-) will yield all dominant allele phenotype (+/-)
2) Heter. dominant (+/-) crossed with heter. dominant (+/-) will yeild a 3:1 ratio for dominant allele phenotype.
- also used to determine heterozygotes
Describe: Test cross
Cross of an organism with a heterozygous dominant (+/-) phenotype, and a homozygous recessive phenotype.
- Will yield a 1:1 ratio
Describe: Mendels Laws
- Equal segregation: Two copies of a gene separate so that the gametes each have one allele. Each gamete has the same chance of receiving either.
- Independent assortment: Segregation of a pair of alleles for 1 gene is independent of segregation of alleles for another (Metaphase 1)
X^2 Test
Just know it bro
What are the ratios you would expect from a monohybrid, dihybrid, and trihybrid cross respectively?
Monohybrid–> 3:1
Dihybrid –> 9:3:3:1
Trihybrid –> 27:9:9:9:3:3:3:1
