4A Flashcards
(24 cards)
Mendelian segregation?
It allows transmission of “hidden” genetic variation
It is compatible with Darwin’s theory of evolution through natural selection
It is compatible with observations in real populations
It can maintain rare alleles in a population
monohybrid cross
The organisms of a true-breeding line for a single trait, like those true-breeding lines of pea plants that Mendel used, are _____ for the trait of interest (such as seed colour or pod shape).
Homozygous
Mendel’s principle of segregation corresponds to what stage of meiosis?
Separation of homologues in anaphase I
Co-dominant
An individual carries two different alleles of the same gene. These will be located:
On the same spot on the two homologous chromosomes carrying that gene
A reproductive cell, or gamete, has:
One allele for each gene
Which of the following is not a possible source of environmental variation among human beings?
How much exercise you get
What part of town you grew up in
Who your parents are
How much you got to eat when you were growing up
Your annual exposure to sunlight while you were growing up
Who your parents are
What did Mendel do in his genetic research that earlier researchers had not done?
He examined simple characters with two alternative traits
A single character controlled by multiple genes .
Polygenic inheritance
Pleiotropic
Summary:
👉 Pleiotropy = one gene, many effects.
A single gene in chickens controls feather color, bone strength, and growth rate — all at once! 🐓
Linked
Linked means two genes are close together on the same chromosome and tend to be inherited together. 🧬
Example:
A gene for flower color and a gene for pollen shape that are near each other will often be passed on as a pair 🌸
In an organism homozygous for a particular gene:
The same allele of that gene is found at the same locality on both maternal and paternal copies of the same chromosome in the diploid cells
If you crossed a true-breeding yellow seed plant (A/A) with heterozygous yellow seed plant (A/a):
Offspring genotypes would be 1 A/A : 1 A/a
Read carefully. Round pea seed shape is dominant over a wrinkled pea seed shape. From a monohybrid cross of heterozygous round peas, what is the probability that a pea pod containing exactly four peas will have only one round pea? Take all possibilities into account.
12/256
Consider a one-locus system of simple dominance where the presence of at least one G allele results in a green plant, while a genotype of g/g results in a white plant. If a test cross between a green plant of unknown genotype and a white plant yielded 0% white offspring, what does this tell you about the genotype of the parental green plant?
the plant was homozygous dominant
wtf did mendel do
He true breeded peas to test particulate vs blending inheritance. was there a pattern to inheritance
Principle of Segregation (Mendel’s First Law)
Principle of Segregation (Mendel’s First Law)
Each individual diploid organism possesses two alleles for any particular characteristic. The two alleles segregate when gametes are formed, and one allele goes into each gamete (meiosis).
1 allele from each parent.
This does not affect future reproduction
Occurs in anaphase I
Sum Rule
probability of the occurrence of at least one of two mutually exclusive events is the sum of their individual probabilities
Product Rule
Two independant events occurring in succession
Probability of succession
Probability of a gamete getting either allele is random due to the random alignment of chromosomes at metaphase plate
incomplete dominance
Blending of trait/intermediate phenotype for heterozygote both alleles are not completely dominant, only some functional protein is produced. superscripts for alleles
Polymorphism
more than 2 possible alleles for a gene/trait
so like say 1000 alleles for a gene but you only get 2 of the 1000 possible allele. vast variation in genes therefore increased survival
Adaptive radiation
The rapid diversification of an organism from its ancestral species. Forms new species quick.
