If a person has one gene influencing blue eyes but actually...

Key Concepts

Dominant and Recessive Traits

Dominant traits are expressed in an organism's phenotype when at least one dominant allele is present, whereas recessive traits are masked by dominant alleles and only expressed when an individual has two copies of the recessive allele. This concept explains why a trait may be hidden in a heterozygous genotype.

Genotype and Phenotype

The genotype refers to the specific genetic makeup of an organism, while the phenotype is the observable expression of those genetic instructions. Due to interactions between alleles, such as dominance and recessiveness, the phenotype may not always directly reveal all aspects of the genotype.

Mendelian Inheritance

Mendelian inheritance is the fundamental framework for understanding how genetic traits are transmitted from parents to offspring. It is based on the principles of segregation and independent assortment, which describe how alleles separate during gamete formation and combine during fertilization, resulting in predictable ratios of traits in progeny.

Alleles

Alleles are alternative forms of a gene found at a specific locus on a chromosome. They can influence the traits of an organism, and the interaction of different alleles (such as one being dominant over the other) determines the observable characteristics.

Transcript

00:01 All right, so this question is asking, if a person has one gene influencing blue eyes, but actually has brown eyes, blue eyes must be a blank trait.

00:10 A dominant, be recessive, c, sex -linked, or depolygenic.

00:15 So this question obviously gets at your understanding of genetics.

00:19 And genetics plays a big role in studying developmental psychology because it really follows how certain traits, whether they be biological or psychological, may be passed down, from parents to offspring.

00:33 So the way i'm going to approach this question is just to go by all the options we have and use the process of elimination.

00:39 So the first thing this sticks up to me and probably being the easiest to explain is sex -linked.

00:46 And a sex -link trait is basically a trait that is more influenced, obviously, by the sex of an individual.

00:56 And for example, if a mother has a y, has the trait of color blindness on x chromosome, she is more likely going to pass that onto her son because the father will only contribute on the y chromosome.

01:22 The mother is going to contribute by the x chromosome and the father is going to contribute by the x chromosome, the y chromosome.

01:27 So if the colorblinded trait on the x chromosome is passed down to the individual with x and y chromosomes, making that a male, that their son is more likely to have colorblindness rather than their daughter because a daughter will have an xx chromosome because she is a female.

01:51 So in that way, traits are sex linked because of being passed down from mothers to sons, and they're more likely to be expressed.

02:03 So just to put that into simple words to remember, i like to just remember it by traits, follow, or are influenced by sex.

02:16 And going back to the question, it's saying that if a person has one gene influencing blue eyes, but actually as brown eyes, blue eyes must be.

02:22 So the question doesn't really or actually doesn't at all mention any sort of sex involved.

02:29 So c can be eliminated.

02:33 Right, below that we have polygenic.

02:35 And polygenic is probably one of your least known terms when talking about genetics and studying psychology.

02:41 But it's really easy to break it down, heli linguistically.

02:45 We know that poly means many...

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