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A heterozygote means different-joined
a homozygote means same-joined
so lets look at this cross. (parent genotype are Bold and italics)
---B----b
B | BB | Bb |
--------------------
B | BB | Bb |
We see that 2 "joined" zygotes are BB and 2 are Bb
SO by definition 2 combinations produce a heterozygote "Bb"
and 2 produce a homozygote "BB"
What else can I help you with?
In certain rats black fur is dominant over white fur If two rats both heterozygous for fur color are mated their offspring would be expected to have?
There different genotypes and two different colors Black fur is dominant --> F White fur is recessive --> f The parents are bot Ff (heterozygotes, and because black fur is dominant they have a black fur). If they mate, you get parents: Ff x Ff Offspring: FF Ff Ff ff so 25% will be homozygous for Black fur 2x25=50% will be heterozygous, and have a Black fur and 25% wil be homozygous for White fur. Hence, of their offspring, 75% will have a black fur and 25% will have a white fur
In a BB x bb cross?
In a BB x bb cross, all offspring will have the genotype Bb. The offspring will exhibit the dominant trait of the B allele.
What are dominant and recessive alleles with examples?
dominant alleles will always overrule recessive alleles. So if you have any dominant allele in the phnotype or geneotype, the dominant trait will be expressed. For example, since black fur is dominant to brown fur on mice, if two black mice mate, at least part of their offspring will have black fur. If they are heterozygous for black, though, that's when a brown mouse offspring may be possible, but there would always be more black offspring than brown offspring. parents offspring (4) Bb x Bb --> BB, Bb, Bb, bb BB x Bb --> BB, BB, Bb, Bb BB x BB --> BB, BB, BB, BB BB x bb --> Bb, Bb, Bb, Bb Bb x bb --> Bb, Bb, bb, bb anything with a capital B would be black while "bb" is the only brown.
What is the generation of the offspring of a cross between parents that are pure for a given trait?
The first generation cross, known as F1 (filial 1), for homozygous (purebred) parents will be heterozygous - have one allele of each of their parents' traits. For example, the cross BB X bb would result in an F1 genotype of Bb.
What is the genotypes of offspring from the following cross AABB x aabb?
You make a box with 4 boxes in it and then you plug in the parents on the top and the side, which is the BBxBb, and match up the alleles (the letters) like coordinates in a graph. BBBBBBBBbBbb
Show the cross between 2 heterozygous dogs. black fur B is dominant to brown fur b?
The Punnett square for crossing two heterozygous dogs (Bb x Bb) would result in a 25% chance of offspring with homozygous dominant black fur (BB), a 50% chance of offspring with heterozygous black fur (Bb), and a 25% chance of offspring with homozygous recessive brown fur (bb).
In certain rats black fur is dominant over white fur If two rats both heterozygous for fur color are mated their offspring would be expected to have?
There different genotypes and two different colors Black fur is dominant --> F White fur is recessive --> f The parents are bot Ff (heterozygotes, and because black fur is dominant they have a black fur). If they mate, you get parents: Ff x Ff Offspring: FF Ff Ff ff so 25% will be homozygous for Black fur 2x25=50% will be heterozygous, and have a Black fur and 25% wil be homozygous for White fur. Hence, of their offspring, 75% will have a black fur and 25% will have a white fur
In a BB x bb cross?
In a BB x bb cross, all offspring will have the genotype Bb. The offspring will exhibit the dominant trait of the B allele.
A homozygous dominant black bear is mated with a recessive brown bear what phenotype will probably result in the offspring of the two bears?
Phenotype: Black Bear x Brown Bear Genotype: BB x bb Possible gametes: B B b b Possible B B crosses: b Bb Bb b Bb Bb Phenotype of offspring: Only Black bears
How do you solve the phenotype and genotype of a punnet square?
Well it depends on how many of each that you have. Let's start simple. Let's say your mom has brown eyes which is a dominant gene meaning it has a capital B and your dad has blue eyes which is a recessive gene which means it has a lower case b. So mom can either be Bb or BB in order to have brown eyes, but dad is definitely bb because he has blue eyes. So let's just say mom is BB. So for this punnet square you would only need four squares. On the top two you put a B and a B on each square which stands for mom's gene. On the side of the square you put b and a b on each of the two squares which stand for dad's genes. Now all you do is write the new gene in each box. For the top left hand box you would write bB since that b is what dad gives and B is what mom gives. For the top right hand box you write bB again since that is what mom and dad is giving off. Then you do the bottom two squares the same way. Now let's say we want to add height to this. Dad is tall so he is T. Mom is short so she is t. You use the punnet squares again in the exact same way. Place mom's genes on the top and dad are on the bottom. You can also figure out probabilities of genotypes and phenotypes by doing fractions. Someone who is BB or bb is homozygous (means same) for that gene. Someone who is Bb is heterozygous (means opposite). Anyone who is homozygous dominant (BB) that mates with a homozygous recessive (bb) person will result in a punnet square with ¼ Bb, ¼ Bb, ¼ Bb, and ¼ Bb meaning that all of their children will have brown eyes. Anyone who is homozygous dominant (BB) that mates with a heterozygous (Bb) will have ¼ BB, ¼ Bb, ¼ Bb, and ¼ bb. So ¾ of the children will be brown eyed and ¼ blue eyed. If you have heterozygous (Bb) mate with a homozygous (bb) you will have ½ Bb and ½ bb. Using fractions would be easier if you can't get the punnet squares correct.Below is an example of how to do more than one trait.Ex. In peas, tall (D) is dominant to dwarf (d) and yellow cotyledons (G) is dominant to green (g). If a tall, heterozygous pea plant with green cotyledons is crossed with a dwarf pea plant heterozygous for yellow cotyledons, what will be the phenotypic results in the progeny?Ddgg x ddGgDg dg x dG dgdGdgDgDdGgDdggdgddGgddgg½ D ½ d 1g ½ DgProbability of tall ½Probability of short ½Yellow ½Green ½Tall and yellow (1/2 x ½)= ¼Tall and green (1/2 x ½)= ¼Dwarf and yellow (1/2 x ½)= ¼Dwarf and green (1/2 x ½)= ¼
Genotypic ratio of a dihybrid cross?
Hey there. Ive typed up a couple to use as examples using the brown hair. You must take into account the recessive and dominant traits, as this could range your answer being different. A phenotype is the result of a genotype, which is the result of 2 alleles. Say if both parents were HOMOZYGOUS for brown hair, with their genotype would be BB, BB. Use a trick called a punnet square to answer this; _|B |B | B|BB|BB| <-- not the best punnet square, but the top row shows the first parents B|BB|BB| genotype (BB) and the side shows the second's. (BB) The cross of this shows all the children will have brown hair, as inherited from each parent. If the Mother had HOMOZYGOUS brown hair (BB), and the father had HETEROZYGOUS brown hair (Bb) the results would be 100% Brown hair too, because the brown hair gene (B) is dominant over the non brown hair gene (b). Below; _|B |B | B|BB|BB| <--- this shows the cross gives a 50% chance to be Homozygous for brown b|Bb|Bb| hair but 50% heterozygous for brown hair, but carrying a non- brown hair gene. If we cross 2 heterozygous parents, the results are shown: _|B |b | B|BB|Bb| b|bB|bb| <----- This shows the child has a 75% chance of having brown hair (either (BB or bB, Bb) and 25% of being non-brown (bb)). This can be used in any gene cross, but you must keep in mind that one gene will be dominant and one will be recessive. I used the brown hair gene as an example here, as I don't know whether it may be dominant or recessive to other hair colours. Also, if you were after a global statistic, I wouldn't know. I hope this helps you. Fletch
What are dominant and recessive alleles with examples?
dominant alleles will always overrule recessive alleles. So if you have any dominant allele in the phnotype or geneotype, the dominant trait will be expressed. For example, since black fur is dominant to brown fur on mice, if two black mice mate, at least part of their offspring will have black fur. If they are heterozygous for black, though, that's when a brown mouse offspring may be possible, but there would always be more black offspring than brown offspring. parents offspring (4) Bb x Bb --> BB, Bb, Bb, bb BB x Bb --> BB, BB, Bb, Bb BB x BB --> BB, BB, BB, BB BB x bb --> Bb, Bb, Bb, Bb Bb x bb --> Bb, Bb, bb, bb anything with a capital B would be black while "bb" is the only brown.
If a homozygous dominant is crossed with a homozygous recessive for a given trait the offspring will be?
The phenotype will show the dominant trait. All dominant traits mask recessive ones; If the genotype is heterozygous (One dominant and one recessive) the organism's phenotype will be dominant.
What is the generation of the offspring of a cross between parents that are pure for a given trait?
The first generation cross, known as F1 (filial 1), for homozygous (purebred) parents will be heterozygous - have one allele of each of their parents' traits. For example, the cross BB X bb would result in an F1 genotype of Bb.
What is an example of two heterozygous parents?
The possible genotypes of parents who are heterozygous would be found using a punnet square. The outcome would be 50 percent heterozygous dominant, 25 percent homozygous dominant, and 25 percent homozygous recessive.
If two black cows have a baby cow what color will that cow be?
Two cows cannot mate to get a calf (or "cow" in this instance). You have to have a BULL and a cow to get a baby calf. Just like you gotta have a Mom and a Dad to "make" you.Now back to the question. If the bull is black and the cow is black, there is a high chance that you will get a black calf. However, let's increase the complexity and throw in a bit of genetic terminology in here.Let B = black and b = red. Black is always homozygous or dominant to red in cattle.If both the sire and dam is heterozygous black (Bb x Bb) , there is a 25% chance that you will get a red calf (bb). But if both parents are homozygous for black, there is a 100% chance that the calf will not be red, but instead, homozygous black (BB). If either one of the parents are heterozygous black, the calf still has a 100% chance that it will be black, phenotypically. But, genotypically, the calf has a 25% chance of being heterozygous black. A heterozygous black calf, no matter if it grows into a cow or a bull (depending on the calf's sex), will have a 25% chance of giving birth to or siring red calves if crossed with a heterozygous black bull or cow or a a 75% chance of siring a red calf with a red bull or cow.
What is the genotypes of offspring from the following cross AABB x aabb?
You make a box with 4 boxes in it and then you plug in the parents on the top and the side, which is the BBxBb, and match up the alleles (the letters) like coordinates in a graph. BBBBBBBBbBbb
