Basic Genetics Flashcards
Describe Population Genetics?
The study of genetic traits withing a large population:
- Mendel’s law of inheritence
- Hardy-Weinberg Principle
- Inheritance patterns
Cellular genetic pertains to?
The cellular organization of genetic material
Molecular genetics pertains to?
The biochemistry of genes and the structures that support genes.
Wohat are genes?
A section of DNA on a chromosome
What are alleles?
One of two or more diffefrent allels that occupy a specific locus on a chromosome
What does the locus refer to?
The specific location of a gene on a chromosome.
What is a Amorph?
A silent gene; gene that does not produce a detectable antigen, such as Jk, Lu, O
What is genotype?
Individuals genetic makeup (inherited genes)
Phenotype?
Produced by the geneotype, it is the observable characteristics.
Ex: an enzyme to control blood group antigens; bone length (height)
What is a Dominant gene?
Characteristic expresses even if carried on one of the homologous chromosomes.
What is a recessive gene?
A gene that in the prescence of its dominant allele is not expressed.
What is a co-dominant gene?
Both genes are expressed, they are not dominant over one another.
What is Homozygous?
Same allele on both chromosomes
What is Heterozygous?
Different alleles on both chromosomes
Autosomal?
A trait not carried on the sex chromosomes
What is autosomal dominant?
Traits physically expressed by all members of the family that carry of the allele.
***A pattern of inheritance in which an affected individual has one copy of a mutant gene and one normal gene on a pair of autosomal chromosomes.***
What does Prokaryotic mean?
organism without a defined nucleus (bacteria and archea)
What does Eukaryotic mean?
With a nucleus (all mammals)
What are Histones?
Long polymers of DNA and various proteins that are compacted to form chromosomes during cell division.
Who was Gregor Mendel?
What did Mendel refer to genes as?
An Austrian monk and mathmatician that observed pea plants to study how physical traits are inherited.
Elementen
Who does Medel’s law apply to?
All sexully producing dipliod organisms
What observable characteristics did Mendel study in pea plants? (3)
- Flower color
- Seed color
- Seed shape
What did Mendel base his first law; the law of inheritance on, the law or independent or random segregation?
His results from his observations of the flower and seed color and seed shape from the pea plants
What is Mendel’s First Law?
Law of independent segregation (random segregation)
Alleles have no permenent effect on one another when present in the same plant but segregate unchanged by passing into different gametes.
Mendel’s 2nd Law:
If a homozygote dominant for two characteristics is crossed with a homozygote tha is recessive for both characteristics, what phenotype will the offspring have?
Offspring will have the same phenotype as the dominant parent.
What is Mendel’s 2nd Law?
What in his studies did he base this law on?
The law of independent assortment
Different types of seeds produced by peas (green, yellow and textured; smooth / wrinkled)
What is the first generation of Mendel’s study called?
What color were the flowers (trait)?
Parental pure (P1)
All red or all white (homozygous)
What is the First Filial generation and what trait was observed in their offspring?
- P1 generation was crossbred producing the second generation called First Filial (F1) that were all red.
- Dominant trait is the only trait observed. All plants are heterozygous (hybrid) for flower color (Rr)
What happened when the F1 generation were crossbred to eachother? What is the name of the generation was produced?
Why was this result produced?
- Red to white flowers produced in a 3:1 ratio
- Second-filial (F2)
- Because plants that have the R gene are either RR (homo) or Rr (hetero) have red flowers because red gene is Dominant.
- White flower is recessive and must occur in rr to be visible phenotype.
When is Partial Dominance observed?
What is important to remember regarding the above phenotype?
When the phenotype of a heterozygous organism is a mixture of both the homozygous phenotypes seen in P1
Although the phenotype does not show dominance or recessive traits, the F1 generation has the heterozygous type Rr.
How are most blood groups inhertited?
- Co-Dominant manner
What is Co-Dominance?
Both alleles are expressed, and their genes seen at the phenotypic level.
Example: a heterozygous MN individual will type as both M and N antigen positive.
What are Punnett squares?
Used to determine the possible ways alleles can combine to express a phenotype.
What are the Exceptions to Mendel’s Laws?
- Genes for a seperate trait closely linked on a chromosome, can be inherited as a single unit
- Differences in gene ratios of progeny of F1 mating, if recombination has occured by meiosis.