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Why are recessive X-linked traits more likely to be expressed in a male fruit fly than a female fruit fly?
This one is easy for me, because I'm colour-blind. That is also a recessive X-linked trait, and Drosophila have their sexes determined in the same way as humans, so I'm in the same boat. We humans and flies have a certain number of chromosomes in pairs, then two others, called the X chromosome and the Y chromosome.
When you have an unusual recessive gene on a paired chromosome, it is usually masked by the gene on the other of the pair. Usually, the things we notice are absences, deficiencies, things that go wrong, and the reason things have gone wrong is that some chemical or other is not being made, because the instructions are scrambled. When there are two versions of the gene, the non-mutant form pretty well covers for it, making enough of the missing chemical to hide the effect.
Females have two X chromosomes, so the non-faulty X can cover for the other one, but in males, the Y chromosome has very little useful information on it, so white eye shows up in a male Drosophila, and colour blindness shows up in me. There was just no second copy there to hide the trait.
This is actually a bit too simple: women who are carriers for G6PD deficiency have measurably lower levels of G6PD. Other confounding factors: in humans, one of the X chromosomes is wrapped up and turned off. The tortoiseshell coat in some female cats is caused because coat colour is X-linked in cats, and the colour at any point depends on which X chromosome is turned off.
This was explained by a lovely geneticist called Mary Lyon, who was still working, last time I emailed her with a question.
What else can I help you with?
What is the most likely mode of transmission for a trait that is not expressed in parents but is expressed by one half of the sons?
Rare X-linked recessive
Why are recessive alleles not always expressed as the phenotype?
recessive alleles get masked to show the difference in a dominant gene and a recessive gene. the dominate genes masks the recessive genes to show that the dominate gene is more dominate or more likely to be the outcome than the reccessive gene but the masked gene is not always recessive.
Are dominante and recessive genes responsibile for how baby looks?
Yes, dominant and recessive genes play a role in determining physical traits in offspring. Dominant genes are more likely to be expressed in the phenotype, while recessive genes are typically masked unless an individual inherits two copies of the recessive allele. This interplay between dominant and recessive genes contributes to the variety of physical characteristics seen in offspring.
The stronger of the two traits which show up in an organism is called a?
dominant trait. It is more likely to be expressed in the phenotype of an organism when it is inherited with a recessive trait.
What is a dominent allele?
A dominant allele is an allele that can take over a recessive allele, so if you have a dominant allele and a recessive allele, then the offspring will most likely have a dominant allele over a recessive allele. The dominant allele is expressed over the recessive allele.
What are genes that are less likely to be expressed called?
A recessive gene
What is the most likely mode of transmission for a trait that is not expressed in parents but is expressed by one half of the sons?
Rare X-linked recessive
Why are recessive alleles not always expressed as the phenotype?
recessive alleles get masked to show the difference in a dominant gene and a recessive gene. the dominate genes masks the recessive genes to show that the dominate gene is more dominate or more likely to be the outcome than the reccessive gene but the masked gene is not always recessive.
Why are males more likely than female to have a sex linked trait that is recessive?
Because they olny have one X chromosome.
What makes dominant alleles different from recessive alleles?
It's in the word! Dominant means bigger or stronger or greater. So the dominant allele is the stronger gene that is going to show whereas the recessive allele is still in you, but is overshadowed by the dominant allele.
Is right-handedness a dominant or recessive trait?
Right-handedness is considered to be a dominant trait, meaning that it is more likely to be expressed in individuals compared to left-handedness.
Are dominante and recessive genes responsibile for how baby looks?
Yes, dominant and recessive genes play a role in determining physical traits in offspring. Dominant genes are more likely to be expressed in the phenotype, while recessive genes are typically masked unless an individual inherits two copies of the recessive allele. This interplay between dominant and recessive genes contributes to the variety of physical characteristics seen in offspring.
Difference between dominant and recessive genes?
dominant genes are more likely to be passed down to a child than recessive genes. Here's an example: A woman has black hair and blue eyes. Her husband has blonde hair and brown eyes. Their child will most likely have brown eyes and black hair, because black hair and brown eyes are dominant genes, while blonde hair and blue eyes are recessive. It is, of course, still possible for the child to be blonde and blue-eyed, only less likely. However, if the father had blue eyes too, it would be most likely that the child would have blue eyes. Grandparents are also a factor: say that both parents have blue eyes, but one or more of the child's grandparents (or anyone down the genetic line, actually) has brown eyes. It is therefore also possible for the child to have brown eyes. hope it helped
In the family tree below people with the recessive trait of attached earlobes are shaded gray.?
a male with one recessive allele
How are dominant and recessive genes related?
Dominate them. Recessive alleles do not show in your phenotype unless you have two of the same recessive allele. But if you inherit one dominant and one recessive, it is the dominant that always shows in your phenotype.
The stronger of the two traits which show up in an organism is called a?
dominant trait. It is more likely to be expressed in the phenotype of an organism when it is inherited with a recessive trait.
Why would recessive traits be more common on boys than girls?
Only sex-linked recessive traits on the X sex chromosome are more common in males. This is because males receive only one X chromosome, so they cannot be heterozygous for a trait on the X chromosome. Females inherit two sex chromosomes, so they can be heterozygous, receiving both a dominant and a recessive allele on the X chromosomes.
