Genetics 1 Flashcards
What is asexual reproduction
- Reproduction w/out fertilization or conjugation
- Parent passes 100% of genes to all offsprings
i. e. budding, fragmentation
What is sexual reproduction
- Occurs thru fertilization to produce genetically novel individual
- Each parent passes ~50% of its genes to each offspring
- Offspring tend to resemble parents
- Internal and external fertilization
DNA organized into ___
Chromosomes
Describe somatic cells
- All cells in body cept sex cells
- Diplod (2n)
- Produced from diploid cell by mitosis
Describe gametes
- Eggs and sperm
- Haploid
- Produced from diploid cell by meiosis
3 sources of genetic variation
- Crossing over
- Independent assortment
- Random fertilization
What is crossing over
Exchange of corresponding segments of DNA by non-sister chromatids in a tetrad during prophase I
What is independent assortment
Random alignment of each pair of homologous chromosomes at Metaphase I plate
3 advantages of sex
- Introduces new combinations of heritable traits in offspring
- Accelerates the rate of evolution
- Potentially useful in variable, dynamic environment
Steps to go from genes to traits
DNA (gene) -> protein -> character -> trait
On homologous chromosomes, the linear sequence of genes is identical but ___ may differ
Alles
What are mendelian genetics
The scientific study of how traits are passed on from parent to offspring
The study of heredity
What is mendel’s first law of heredity
Law of segregation
The two alleles for a heritable trait separate during gamete formation and end up in different gametes
What is mender’s second law of heredity
Law of independent assortment
Each pair of alleles segregates independently of each pair of alleles during gamete formation
