Heredity Flashcards
what were some ancient ideas about inheritance?
- Hippocrates - Pangenesis
- Aristotle - form + potentiality = actual form
- Hybridization of diff kinds of animals yielding an off-spring that is intermediate looking
- Inheritance of acquired characteristics
- Genetic purity - can be disastrous for vertebrates but might work for plants . E.G. - pure bred dogs face so many health conditions due to this genetic purity factor
- The idea about inheritance being preformationist or epigeneticist was also a question back then
- Blending inheritance : Blending inheritance is an outdated genetic theory which posited that offspring are a smooth blend of their parents’ traits. According to this theory, the traits of the parents mix in the offspring like colors of paint, leading to an intermediate phenotype. For example, if one parent had a tall stature and the other was short, blending inheritance would predict that their children would have a medium height.
8, Bible - experiences of mother are highly influenced by their environment like the stripped cow example
Gregor Mendel was a part of _______
Augustinian Order of Brno
What experiment did Mendel Perform in the 1850s to 1860s
Pea hybridization
What were the reasons that Mendel succeeded?
- He used garden pea which has multiple benefits
- His work was not based on previous theories but just mere observation that offsprings resemble their parents
- He asked narrow questions and built a testable model to explain his observations
- quantitative work
what is segregation of traits?
Traits are controlled by pairs of genes, with each parent contributing one gene. These genes can have different forms called alleles. During the creation of eggs or sperm, the gene pairs split up, so each egg or sperm gets just one allele. When fertilization happens, the offspring gets one allele from each parent. This mixing can create different combinations of traits. For example, if a parent has alleles for tall (T) and short (t) height, their gametes will either have T or t, which combine with the other parent’s alleles in the offspring, leading to various height outcomes.
What did Mendel observe and conclude from his Pea hybridization experiment?
- Segregation of traits :Mendel concluded from these observations that traits (alleles) segregate or separate from each other during the formation of gametes (eggs and sperm). Each parent passes on only one allele for each trait to their offspring. This segregation of alleles during gamete formation and their independent assortment during fertilization explained the patterns of inheritance Mendel observed
- Counting progeny and extracting an abstract model to explain numbers
- Model implied particulate inheritance - Gregor Mendel’s experiments with pea plants showed that traits do not blend together (as previously thought) but are inherited as distinct units (genes) that retain their individuality across generations.
_____ suggested mendel to work with hawkweed and it failed, why?
Karl nageli
Because the plant was apomict implying the females produced embryos without a sperm
Discuss the other models of inheritance in the late 19th century
- Darwins Pangenesis - gemmules that also implied hereditary characteristics were indivisible particles or atoms and not fluids.
- It also observed that the environment tends to influence the hereditary particles - Germplasm Theory by Weismann - distinguished b/w germplasm and somatoplasm cells.
- Observations: In essence, the germplasm theory emphasizes that the characteristics an organism inherits are determined by the genetic material carried in its germ cells, which remain separate from and unaffected by other cells in the body or environmental factors encountered during its lifetime
- hereditary particles exist on the chromosomes - BIOMETRICAL APPROACH
- applying stats to biological problems
- francis galton
- continuous variation (quantitative)
- Biometrical approaches are used in genetics, agriculture (for breeding programs), medicine (to study diseases and treatments), ecology (to understand population dynamics), and many other fields where understanding variation and inheritance is important. In essence, biometry helps scientists apply mathematical and statistical tools to understand and quantify biological variation and relationships within populations.
- Law of Ancestral Heredity - 1/2 from parents and 1/4th from grandparents
What is germplasm vs Somatoplasm?
GERM - Refers to genetic material or DNA carried in germ cells - sperms or eggs
SOMATO - refers to the non-reproductive cells of the body
What is Eugenics
improving the human race by heritably selective reproduction
What 3 currents in the study of inheritance came together?
- Rediscovery of Mendels work
- Understanding chromosome and cell division
- increasing interest in the functional bio
The units of heredity that determine certain characteristics or traits in an organism are called______
Mendelian factors
- in summary, Mendelian factors were Mendel’s conceptual units of inheritance, which we now recognize as genes, responsible for passing on traits from parents to offspring in a predictable manner.
Who was the Dutch Botanist who independently rediscovered the Mendels Observation?
Hugo De Vries
What all did Vries observe?
- traits must be studied as separate hereditary units
- recessiveness and dominance
- reappearance of recessive trait in the F2 generation
- 3:1 ration in the F2 gen
- some F2s bred true while rest segregated
MAIN OBSERVATION: Hereditary units were intracellular pangenes on chromosomes
What did Carl Crrens rediscover?
Particulate inheritance
