17.4 Sex Chromosomes and X-Linked Inheritance Patterns

• The theory of inheri disease is supported by some early evidence.

• Several mechanisms of sex determination were found in different species of animals.
• Human genes are located on sex chromosomes, which are different in a difference in a single pair of sex chromosomes.

• Next, we will consider the inheri tance patterns of these genes.

• In the X-Y system of sex determination, the cells of males and females have different X and Y chromosomes.
• There are 22 pairs of autosomes and one pair of sex chromosomes in the 46 chromosomes carried by human cells.
• The Y chromosome causes maleness in mammals.

• Predict the outcome of crosses when the Y chromosomes of mammals play a key role in the development of the sex chromosomes.

• The X-O system works in many insects.

• The basis for understanding how male and female characteristics are transmitted from ness is not determined by the Y chromosomes in the X-O system.
• Females in this system have sex chromosomes and are parents to offspring.
• We looked at the theory of the chromosomes.
• In some insect species that follow the X-O system, inheritance provides a framework for explaining the male has only one sex chromosomes.
• The sex of an insect is a species.

• The sex of the fly will be determined by whether or not it receives a Y chromosome.
• Sex chromosomes are found in many species of diploid fly, but not all of them have two X chromosomes.
• Sex chromosomes were studied in order to determine if the fly becomes a female.

• We have considered examples where the genes are on the same chromosomes.

• The male of these genes was found to cause disorders in humans in other animal species, such as birds and fish.

• The sex Z-W system is different from the X-Y system found in mammals.

• Sex in animals is determined by chromosomes, but other mechanisms are also known.
• Sex is controlled by temperature in some animals.

• All of them produce males.

• There are flowers that produce female gametophytes.

• Sex determination is done by the sex chromosomes X and Y.
• The male and female plants are different in appearance.

• The Y chromosome is small and has less than 100 genes, whereas the X chromosome is large and has over 1,000 genes.
• Less genes are known to be Y-linked because they are not on the X.

• The term usually refers to X-linked genes because there are fewer on the Y chromosome.
• In mammals, a male can't be described as a Heterozygous for an X-linked gene because there are two copies.
• The circles show the numbers of the X-linked genes.

• If a person is born with only one X chromosomes and no diseases occur more often in males than in females.

• A small cut may bleed for a long time in individuals with the blood disorder.
• A threat of severe inter nal or external bleeding is posed by injuries that are minor in most people.
• A special pair of sex chromosomes are not involved in some chromosomal mechanisms of sex.
• If a mother is a carrier of the disease her children have a 50% chance of getting it.
• The male bee is produced from an unfer after Punnett square shows a cross between an unaffected father and a haploid egg.
• Male bees are haploid.

• The common (wild-type) color is provided by the distinctive inheritance pattern of X-linked alleles.
• The white-eye trait must be able to show that a specific gene is on the X chromosomes.

• The flies did not show a female for many generations.

• Morgan dominated after 2 years of looking at flies.

• The pattern of inheritance of a particular gene may be revealed by a quantitative analysis of genetic crosses.

• A white-eyed male fly was discovered in the population of red-eyed fruit flies.

• The eye color and sexes of the offspring are noted.

• To get F2 generation of offspring, cross F1 offspring with each other.

• The data is consistent with an inheritance pattern in which an eye-color gene is located.

• Sex limited inheritance in flies.

• The pattern of inheritance of a particular gene may be revealed by a quantitative analysis of genetic crosses.

• A white-eyed male fly was discovered in the population of red-eyed fruit flies.

• The eye color and sexes of the offspring are noted.

• To get F2 generation of offspring, cross F1 offspring with each other.

• The data is consistent with an inheritance pattern in which an eye-color gene is located.

• Sex limited inheritance in flies.

• White-eyed females were not observed.

• Any white-eyed females were suggested by the results.
• Morgan's connection between the eye color and sex of the data was confirmed.
• The offspring should also be pointed out.

• A decreased survival rate for white-eyed flies is explained by the lower than expected number of chromosomes.