Produces gametes what type of cell division produces

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Produces gametes What type of cell division produces gametes? Meiosis Genetic Definitions Gene – info (DNA sequence) leading to a particular characteristic DNA sequence codes for a particular protein but leads to characteristic Allele – one form of a gene Ex. blonde or brown hair, purple or white flower pea plants Locus – location of a gene on a chrm So looking at all the DNA within a cell every gene has a particular location along the chrm that it’s found on Phenotype – physical expression of the alleles Ex. purple vs. white flowers Genotype – listing of the alleles for an individual Typically done for just 1 or 2 genes (letters) Two different conditions within genotypes: Homozygous – condition in which both alleles for a gene are the same Ex. genotype where an individual has the 2 recessive (a/a) or 2 dominant alleles (A/A) Heterozygous – condition in which the alleles for a gene are different Ex. A/a **Always write dominant allele first Testcross – cross an individual of an unknown genotype with a homozygous recessive individual Individuals with a dom genotype → don’t really know what their genotype is (could be homo or hetero) The one’s we always know are the recessive genotypes In a testcross always cross unknown with a recessive gene Gamete Formation Rules (about single genes) Thinking about the relationship between meiosis and what that means in terms of producing the final gamete Meiosis is the type of cell division that fundamentally leads to gamete formation 1. An allele can only be present in a gamete if that individual actually contains that allele in their genotype So can’t put alleles into your gametes that you don’t contain within your own genotype 2. For every pairs of alleles, an individual gamete only gets one of the pair 3. Different pairs of alleles assort independently from one another Examples involving Rules 1 and 2: Individuals who is homozygous dominant (A/A) and homozygous recessive (a/a) Looking in their cell, the chrm in there contains the A gene 11
Has the Big A form of that allele on BOTH of the chrms → both members of that hom pair First division of meiosis → members of that pair are separated Each daughter cell gets one member of that pair; each containing a Big A allele Second division of meiosis → those replicated chrms are then separated End up with an individual who has the genotype A/A, can only produce gametes that contain a single Big A The final gamete will only get one member of the pair Individual who is heterozygous Locus for the A allele → have Big A alleles on one chrm and little a alleles on the other End of first division → separate those such that one cell contains a chrm with Big A allele, other cell with little a allele End of second division → half of the gametes are going to contain Big A alleles and the other half are going to contain little a alleles Means person produces gametes in two forms Bc this person has both alleles in their genotype, they can produce gametes with both alleles Example involving Rule 3: Two different pairs of alleles and located on different chrms Individual who is hetero for 2 different genes (A and B gene) and alleles for A and B genes

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